Centennial of Quantum Theory: Progress in Atomic and Molecular Structure - CEQPAS 2025, Book of Abstracts

Centennial of Quantum Theory: Progress in Atomic and Molecular Structure CEQPAS 2025 Book of Abstracts Књига апстраката 3-5 November 2025, Belgrade, Serbia 3-5 Новембар 2025, Београд, Србија https://www.moless-spectroscopy.org/ ii Title: Centennial of Quantum Theory: Progress in Atomic and Molecular Structure - CEQPAS 2025, Book of Abstracts Conference: CEQPAS 2025, 3-5 November 2025 Institute of Physics Belgrade, Pregrevica 118, Belgrade, Serbia Organization: University of Belgrade - Institute of Physics Belgrade University of Belgrade - Institute of Chemistry, Technology and Metallurgy MOLecular Excited State spectroscopy (MOLESs) Consortium Conference Chairs: Nigel J. Mason, University of Kent, UK Bratislav P. Marinković, University of Belgrade, RS Publisher: University of Belgrade - Institute of Chemistry, Technology and Metallurgy Njegoševa 12, 11000 Belgrade, Serbia University of Belgrade - Institute of Physics Belgrade Pregrevica 118, Belgrade, Serbia Editors: Jelena B. Maljković, University of Belgrade, RS Matija Zlatar, University of Belgrade, RS Cover Design and Layout: Felipe Fantuzzi & Cauê P. Souza Cover Photo: Cauê P. Souza - Belgrade cityscape Year of Publication: 2025 DOI: 10.5281/zenodo.17467616 ISBN 978-86-81405-31-4 Copyright: © 2025 The authors of individual abstracts. © 2025 CEQPAS Organizing Committee (compilation, layout, and design). This volume and all the abstracts included are published under the terms of the Creative Commons Attribution 4.0 International License (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/ Disclaimer: The abstracts in this volume are published as submitted by the authors. The editors and organizers assume no responsibility for the accuracy, content, or language of individual contributions. The information contained herein is provided for scientific exchange and may be subject to change. Neither the editors, the Organizing Committee, nor the host institutions accept liability for interpretations, consequences, or typographical errors. iii International Scientific Committee Nigel J. Mason - University of Kent, UK - chair Bratislav P. Marinkovic - University of Belgrade, Serbia - chair Bhalamurugan Sivaraman - Physical Research Laboratory, India Bobby Antony - Indian Institute of Technology (Indian School of Mines) Dhanbad, India David Field - Aarhus University, Denmark Felipe Fantuzzi - University of Kent, UK Heidy M. Quitián-Lara - Max-Planck-Institut für extraterrestrische Physik, Germany Jelena B. Maljković - University of Belgrade, Serbia Juraj Fedor - J. Heyrovsky Institute of Physical Chemistry, Czechia Matija Zlatar - University of Belgrade, Serbia Organizing Committee Nigel J. Mason - University of Kent, UK Bratislav P. Marinkovic - University of Belgrade, Serbia Felipe Fantuzzi - University of Kent, UK Jelena B. Maljković - University of Belgrade, Serbia Matija Zlatar - University of Belgrade, Serbia Session Chairs / Reviewers Bratislav P. Marinkovic - University of Belgrade, Serbia Nigel J. Mason - University of Kent, UK Matija Zlatar - University of Belgrade, Serbia David Field - Aarhus University, Denmark Felipe Fantuzzi - University of Kent, UK iv The organizers of CEQPAS 2025 acknowledge the support by the Science Fund of the Republic of Serbia, #6821, Atoms and (bio)molecules - dynamics and collisional processes on short time scale - ATMOLCOL. v A welcome to CEQPAS 2025 This year we celebrate a hundred years of the Nobel Prize in Physics awarded to James Franck and Gustav Hertz for their ingenious experimental finding that in collisions of electrons with atoms, the energy is absorbed in a quantized manner and proving the Niels Bohr model of the atom. It is also a year when we honour eighty years of Wolfgang Pauli’s acceptance of the Nobel Prize for the discovery of the exclusion principle, named after him, the “Pauli principle”, which underpins our understanding of the structure of matter. These two groundbreaking discoveries formed part of the emergence of quantum mechanics as the basis for unravelling the nature of the atomic and molecular world. Accordingly, 2025 was declared by the United Nations as the “International Year of Quantum Science and Technology (IYQ)”, recognising 100 years since the initial development of quantum mechanics. Hence, we are organising the conference “Centennial of Quantum Theory: Progress in Atomic and Molecular Structure (CEQPAS)” to present the advancements of quantum physics in diverse fields such as: • Atomic and molecular spectroscopy and its applications to atmospheric sciences and astronomy; • Collisions and their applications in plasma physics; • Studies in Chemical physics & physical chemistry; • The application of quantum science to our wider understanding of phenomena, including radiation sciences; • The use of Artificial Intelligence (AI) and Machine Learning (ML) for atomic and molecular data analysis and generation. We are delighted to organise this conference in Belgrade, the capital of the Republic of Serbia, at two institutes of national importance: the Institute of Physics Belgrade and the Institute of Chemistry, Technology and Metallurgy. During the conference, more than 25 speakers will present the state of the art across the different topics represented in the conference; summaries of these talks are presented in this Book of Abstracts. Immediately after the CEQPAS conference, we will hold the inaugural meeting of the MOLecular Excited State spectroscopy (MOLESs) Consortium. This consortium has been established to review the status of our knowledge of the electronic spectroscopy of molecules, revising and extending the classic series of Melvin Robin’s three-volume books on “Higher Excited States of Polyatomic Molecules”. A series of reviews of the electronic state spectroscopy of different molecular series in different phases — vi gaseous, liquid and solid — will be presented together with reviews of different experimental and theoretical methods used to collect this data and a discussion of relevance to important applications. We hope all participants enjoy the scientific content of the conference, allowing new collaborations to be formed. We also hope participants will take the opportunity to explore Belgrade. Finally, we wish to thank all who have contributed to the success of the CEQPAS and MOLESs meeting and who will help to celebrate the IYQ. On behalf of the Scientific Committee, Nigel J. Mason & Bratislav P. Marinković Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 Content A welcome to CEQPAS 2025 v Atomic and molecular spectroscopy and its applications to atmospheric sciences and astronomy 1 Collisions and their applications in plasma physics 10 Studies in chemical physics and physical chemistry 20 The application of quantum science to our wider understanding of phenomena, including radiation sciences 30 The use of artificial intelligence and machine learning for atomic and molecular data analysis and generation 39 Author Index 46 ATOMIC AND MOLECULAR SPECTROSCOPY AND ITS APPLICATIONS TO ATMOSPHERIC SCIENCES AND ASTRONOMY Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 8 Ejected electron spectra from N2O molecule obtained by OHRHA electron spectrometer Bratislav P. Marinković1 (ORCID: 0000-0002-6904-6360), Jelena B. Maljković1 (ORCID: 00000001-9176-2673) and Jozo J. Jureta1 1Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, 11080 Belgrade, Serbia *Correspondence: [email protected] Abstract: Electron spectrometer OHRHA (Jureta et al. 2025) is used to obtain ejected electron spectra from nitrous oxide (N2O) molecule. The spectrum at 101.05 eV incident electron energy and in the range of kinetic energies from 5 eV to 9 eV is shown in Figure 1. The assignments of the peaks should be provided by TD-DFT calculations. Figure 1 Ejected electron spectrum from N2O molecule at 90o angle and101.05 eV impact electron energy. Kinetic energy range is from 5 eV to 9 eV. The most prominent peaks are at the KE=5.38; 5.66; 5.84; 5.94; 6.06; 6.20; 6.34; 6.60; 6.80; 6.90; 7.12; 7.22 (dip); 7.3; 7.44; 7.6 eV. Keywords: Nitrous Oxide; Ejected Electron Spectra. Acknowledgement This research was supported by the Science Fund of the Republic of Serbia, Grant No. 6821, Project title – ATMOLCOL References Jureta J. et al., Adv. Space Res. (2025) doi: 10.1016/j.asr.2025.05.043 -500 0 500 1000 1500 2000 2500 5 6 7 8 9 06.07.2025 Ee = 101.05 eV N2O n2omaj33s.fig 0.020 eV/ ch FRR 5 90° 30.05.2025 n2omaj1b.fig KE / (eV) ( cal.) Electron intensity N2OMAJ1b Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 9 Study of Elastic Electron Scattering Cross Section for Desflurane at 200 eV in the Gaseous Phase Jelena Vukalović1,2* (ORCID: 0000-0001-6704-1905), Francisco Blanco3, Gustavo Garcia4 (ORCID: 0000-0003-4033-4518), Bratislav P. Marinković1 (ORCID: 0000-0002-6904-6360) and Jelena B. Maljković1 (ORCID: 0000-0001-9176-2673) 1Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, 11080 Belgrade, Serbia 2Faculty of Science, University of Banja Luka, Mladena Stojanovića 2, 78000 Banja Luka, Republic of Srpska, Bosnia and Herzegovina 3Departamento de Física Atómica Molecular y Nuclear, Facultad de Ciencias Físicas, 4Universidad Complutense, Avda. Complutense s/n, E-28040 Madrid, Spain Instituto de Matemáticas y Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 121, 28006 Madrid, Spain *Correspondence: [email protected] Abstract: Motivated by the environmental impact of halogenated anesthetics, we investigated elastic electron scattering from desflurane (C3H2F6O) at an incident energy of 200 eV using both experimental and theoretical approaches. The measurements were performed with a crossed-beam setup employing the relative-flow normalization method with argon as the reference gas. Theoretical differential cross sections were calculated within the IAM-SCAR+I (Independent Atom Model combined with the Screening Corrected Additivity Rule and interference effects) framework and compared with the experimental data, showing good overall agreement. Since desflurane, like other volatile anesthetics, is largely exhaled unchanged and contributes to greenhouse gas emissions, these results provide useful parameters for atmospheric modeling and assessing its environmental impact. Keywords: Electron Scattering; Desflurane; IAM-SCAR+I. Acknowledgement This research was supported by the Science Fund of the Republic of Serbia, Grant No. 6821, Project title – ATMOLCOL Figure 2. Differential cross section for elastic electron scattering from desflurane molecule. COLLISIONS AND THEIR APPLICATIONS IN PLASMA PHYSICS Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 11 Quantum phenomena in cold scattering and molecular rocking David Field1 (ORCID: 0000-0002-2049-4189) and Andrew Cassidy 1Department of Physics and Astronomy (IFA), Aarhus University, Langelandsgade, Aarhus 8000C Denmark and INTERCAT at IFA. *Correspondence: [email protected] and [email protected] It is 100 years since Schrödinger and Heisenberg formulated quantum mechanics, a theory which may claim to be the most successful of the past century. We would like to highlight how we may understand some aspects of quantum scattering, specifically those which have little or no analogue in classical mechanics. To do this we will describe the topic of low energy electron scattering by atoms and molecules in which the wave character of electrons is strongly dominant. For example the de Broglie wavelength of a 10 meV electron is 12.3 nm. Collisions between electrons and molecules at thermal energy play a key role in the chemistry and physics of plasmas, ranging from those in space to the chemically active plasmas used for thin film and microcircuit fabrication. In addition we should like to explore a currently classical theory of ‘molecular rocking’ in solids and its possible extension to a quantum description. The examples that we give are based on experimental measurements performed at the synchrotron laboratories at Daresbury SRS (UK), Orsay (ACO, Super-ACO, France) and Aarhus (ASTRID and ASTRID2). We will talk about dissociative attachment to CCl4, to highlight superposition, as well as the Ramsauer-Townsend effect – the grandaddy of quantum scattering. We will mention how high resolution VUV spectroscopy and other techniques, coupled with the spontelectric nature of thin solid films of dipolar molecules (see reference below), can be used to describe the electric field in which constituent molecules experience. We will show that this enables estimates of the angles through which molecules in the solid state, such as nitrous oxide or water ice, may undergo rocking motion of fractions of a degree to tens of degrees. The anomalous case of solid ammonia will also be described. Keywords: Collisions; Cold Electrons: Dissociative Attachment; the RamsauerTownsend Effect; Molecular Rocking in Solids. Acknowledgements: We thank the Villum Foundation and the Danish National Research Foundation for recent funding of these projects References Andrew Cassidy, Martin R.S. McCoustra and David Field, Accounts of Chemical Research 2023 56 (14), 1909-1919 Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 12 Time-dependent vibrational distribution function of N2 in DCpulsed plasma Goran B. Poparić1* (ORCID: 0000-0002-6794-4976) 1University of Belgrade, Faculty of Physics, Studentski Trg 12, P. O. Box 44, 11000 Belgrade, Serbia *Correspondence: [email protected] Abstract: Vibrational distribution population of the N2 gas molecules in the condition of low temperature and low pressure DC-pulsed plasma has been theoretically investigated. The calculation was performed by using an extended Monte Carlo simulation of electron transport trough the N2 gas merged with master equations solver for tracking V-V and V-T vibrational kinetic due to gas collision processes. The simulation includes the processes of vibrational excitation and de-excitation induced by collisions of accelerated electrons in DC-pulsed electric field and the gas molecules. The processes of fast V-V redistribution during the molecule-molecule collisions are also tracked together with relatively slow V-T energy transition processes. All of these processes mutually dictate the temporary state of vibrational distribution population of the N2 molecules in low temperature and low pressure plasmas. The DC-pulsed plasma parameters, like value of electric field strength, pulse time and pulse pause time determine the dynamic of vibrational distribution development. Also, number of the pulses in a burst has influence to final population distribution. All of these parameters are varied in the simulation and results show a high impact of these modulated parameters on development and discharge evolution of vibrational distribution. A special attention was dedicated to vibrational distribution quenching at post discharge time. Also, the influence of different electron concentration to vibrational distribution is analyzed and different physical mechanisms which contribute to spreading of vibrational distribution were revealed. Keywords: Vibrational Excitation; V-V and V-T Kinetic; DC-pulsed Plasma; Low Temperature Plasma. Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 13 The quantum collision theory of electron scattering Bobby Antony1, * (ORCID: 0000-0003-2073-9681), Sudhanshu Arya1, Ashutosh Yadav1 1Indian Institute of Technology (Indian School of Mines) Dhanbad, India *Correspondence: [email protected] Abstract: Electron scattering from atoms, molecules, and ions underpins electroninduced chemistry in low-temperature plasmas, semiconductor fabrication, astrophysical spectroscopy, and radiation biology. Reliable, highly accurate electron scattering cross sections are therefore essential inputs to advances in science and technology. This presentation will summarize recent progress and outlines a roadmap showing how developments in quantum theory and computation have reshaped collision theory in general. We trace the roadmap from Schrödinger-based partialwave scattering to fully relativistic Dirac formulations that include spin effects. The discussion surveys methods across energy regimes and the problems they were built to solve. In the low electron energy domain (around ~0 to 20 eV), close-coupling approaches like R-matrix variants—provide detailed treatment, especially considering exchange and polarization effects and can resolve resonances due to the formation of a transient excited state. In the intermediate to high-energy region (~20 to 5000 eV), beyond which excitation and ionization channels become prominent, methods such as optical potential, Born approximations, distorted-wave models, etc. offer efficient and practical predictions of various cross sections with relatively less computational power. For heavier targets and spin-resolved observables, relativistic Dirac-based formulations incorporating spin–orbit coupling further refine thresholds and angular distributions. All these methods have delivered high-accuracy integral, differential, and momentum-transfer cross sections across wide energy ranges. Previous bottlenecks, including restricted target descriptions and challenges in benchmarking unstable species, have been alleviated through enhanced electronicstructure inputs (such as DFT-optimized geometries), refined continuum bases, scalable solvers and software ecosystems, and curated databases that facilitate comparison and data reutilization. Other significant problems encompass scalable relativistic methodologies for complex polyatomic systems, integration of nuclear dynamics and dissociative pathways in the calculation, forward-angle scattering, excited-state targets, and comprehensive end-to-end uncertainty quantification. At the time of the meeting, we will present the most recent results obtained using optical potential and R-matrix methods. However, there are various difficulties that are being encountered presently when investigating complex systems (like heavy, cyclic, polar, etc.), which will also be discussed during the meeting. Keywords: Quantum Collision; Electron Scattering; Optical Potential; R-matrix; Cross Section. Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 14 Low-energy electron beam-induced dissociation of molecules mediated via symmetry lowering Pamir Nag1,* (ORCID: 0000-0002-1530-6104) Miloš Ranković1 (ORCID: 0000-0003-1317-0132) and Juraj Fedor1 (ORCID: 0000-0002-4549-9680) 1J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague 182 00, CZ *Correspondence: pami[email protected]as.cz Abstract: In many cases, upon electron or photon interaction with a molecule, direct dissociation without geometric distortion is not possible due to symmetry constrain. For example, chlorobenzene, a planar molecule, 𝜋∗ resonance cannot dissociate without geometric distortion [Burrow 1986]. We will discuss the effect of geometric distortion and resulting symmetry lowering in low-energy electron molecule collision studies. We used an electron energy loss spectrometer (EELS) and dissociative electron attachment – quadrupole mass spectrometer (DEA-QMS) setup to study vibrational excitation and N—H bond cleavage in pyrrole molecule. Whereas a DEA-VMI (dissociative electron attachment – velocity map imaging) spectrometer to study low-energy electron beam induced dissociation of four unsaturated chlorohydrocarbons, vinyl, allyl benzyl chloride and chlorobenzene. We experimentally showed that in pyrrole molecule the N−H bond cleavage following resonant electron attachment is allowed and controlled by the motion nondissociating carbon-attached hydrogen atoms [Kumar 2022]. The dissociation of the four above-mentioned chlorohydrocarbons is mediated via formation of the lowest shape resonance. In the planar compounds, vinyl chloride and chlorobenzene, due to symmetry constraint the anions (𝜋∗ resonances) cannot dissociate without a geometry distortion [Burrow 1986]. Whereas for the non-planar molecules, allyl chloride and benzyl chloride, the shape resonance has a mixed 𝜋∗− 𝜎∗ character and can dissociate without any geometric distortion. We have measured the angular distributions of the Cl− fragments produced from all the above-mentioned unsaturated chlorohydrocarbons. Our goal was to find out the imprints of the dynamical situation on the angular distribution of the Cl− fragments [Nag 2021]. We found all the four molecules show distinct angular distributions. We have interpreted our results with the help of a single-electronic-state model in the axial recoil approximation. Keywords: Dissociative electron attachment; Symmetry Lowering; Velocity Map Imaging; Electron Energy Loss. References Burrow, P. D, et al., 1986: Chem. Phys. Lett. 132 441-447; Kumar, T. P. 2022, et al., J. Phys. Chem. Lett., 13 11136; Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 15 Nag P. et al 2021 Phys. Rev. A. 103 032830. Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 16 Stark effect in low temperature plasma Nikola Cvetanović1,* (ORCID: 0000-0002-9806-3469), Bratislav M. Obradović2 (ORCID: 00000002-3221-7779) 1University of Belgrade, Faculty of Transport and Traffic Engineering, 11010 Belgrade, Serbia 2University of Belgrade, Faculty of Physics, 11001 Belgrade, Serbia *Correspondence: [email protected] Abstract: Historically, Stark effect has been one of the bedrock phenomena for the quantum theory of atoms. Today it is well explained, though its precise calculation is mathematically demanding, except for hydrogen. It was firstly observed in specially designed experiments with a strong electric field but it also occurs in laboratory plasma, and even in some cases in astrophysical plasmas. Specifically, in plasma discharges, the charge density from ions and free electrons is governed by the Poisson equation, and at the boundary always exist a thin layer, so called ‘sheath’ region. This sheath is a consequence of charge separation and is characterized by a strong macroscopically directed electric field. Examples are near-electrode spaces and plasma streamer heads. Since atoms in the sheath undergo Stark effect, their spectral lines are split and shifted according to the electric field strength. Therefore, Stark effect can be used as a diagnostic tool for measuring one of the most important plasma parameters, the field that regulates particle fluxes. It was found that the ab-initio bases and nonprotrusive nature of this spectroscopic emission method is perfect for examination of spatiotemporal development of plasma. Initially, Hydrogen Balmer series were the most used lines (Ganguly 1991, Videnovic 1996, Cvetanovic 2017). Helium, being a more complicated system, requires a hydrogen-like potential approximation for higher levels, giving a linear effect (Foster 1927, Kuraica 1997, Cvetanovic 2015). Recently, helium Stark spectroscopy has found new application in nonthermal atmospheric pressure discharges that are the most investigated and most promising type of laboratory plasma sources in the last two decades (Obradovic 2017). Keywords: Stark Effect; Plasma, Spectroscopy; Electric Field. References Cvetanovic N. et al., J. Phys. D: Appl. Phys. 48, 205201 (2015) Cvetanovic N. et al., Eur. Phys. J. Appl. Phys. 71: 317 (2017) Foster J. S., Proc. R. Soc. Lond. Ser. A 117 137 (1927) Ganguly B.N., Garscadden A., J. Appl. Phys. 70, 621 (1991) Kuraica M.M., Konjevic N., Appl. Phys. Lett. 70, 1521 (1997) Obradovic B.M. et al., Eur. Phys. J. Appl. Phys. 77: 30802 (2017) Videnovic I.R., Konjevic N., Kuraica M.M., Spectrochim. Acta B 51, 1707 (1996) Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 17 Processes in atmospheric pressure plasma used for application in water treatment – dynamics of reactive species Nikola Škoro1 (ORCID: 0000-0002-0254-8008), Olivera Jovanović1 (ORCID: 0000-0003-26331580), Tomoyuki Murakami2 (ORCID: 0000-0003-0618-2055) and Nevena Puač1 (ORCID: 0000-0003-1142-8494) 1Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade, Serbia 2Department of Science and Technology, Faculty of Science and Technology, Seikei University 3-3-1 Kichijoji-Kitamachi, Musashino-shi, Tokyo 180-8633, Japan *Correspondence: [email protected] Abstract: Non-thermal Atmospheric Plasmas (NAPs) have ability to create a chemically reactive plasma volume (containing ions, radicals, excited species etc.) with overall gas temperature at ambient temperature. In the last decades, interactions between NAPs and liquids (mainly water) have gained tremendous importance in the context of applications in environmental remediation, decontamination and, more recently, medical, and agricultural applications (Kumar, 2021; Puač and Škoro, 2025). In such systems reactive species created in plasma in collisions with electrons and heavy particles interact further with the liquid. For all applications it is important to understand the dependence of concentrations of reactive species deposited in water (e.g. H2O2, NO2-, NO3-) on plasma conditions - entangled task due to complexity of the system (Bruggeman, 2016). So, in this work, we employed experimental measurements and modeling to study a creation and dynamic of reactive species in a system where NAP was in contact with water. The study aimed to gain deeper insight into the reaction pathways: of the reactions initiated in the gas phase, with special focus to OH radicals, and also of liquid-phase processes responsible for the formation of long-lived species significant for applications. We used an atmospheric-pressure plasma jet in a pin-electrode configuration operating with addition of Ar at kHz frequency range of excitation signal that produced a streamer-like discharge which was in contact with a water sample. We performed electrical characterization, optical emission spectrometry and obtained spatial emission profiles of important reactive species in the discharge. In order to comprehend interaction between plasma and liquid a zero-dimensional gas–liquid model was developed and results were compared with measurements of concentrations of reactive species in the treated water. Keywords: atmospheric pressure plasma, reactive species, water treatment, gas–liquid model Acknowledgement: MSTDI Republic of Serbia grant number 451-03-68/2025-14/200024. Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 24 Modulating electrostatic potential as a strategy to control mechanical sensitivity of high-energetiy materials Danijela Kretić1 (ORCID: 0000-0002-1382-8785), Ivana Veljković2 (ORCID: 0000-0003-05844053) and Dušan Veljković1, * (ORCID: 0000-0002-1382-8785) 1University of Belgrade – Faculty of Chemistry, Studentski trg 12 – 16, Belgrade, Serbia 2University of Belgrade – Institute of Chemistry, Technology and Metallurgy – National Institute of the Republic of Serbia, Njegoševa 12, Belgrade, Serbia *Correspondence: [email protected] Abstract: Achieving the balance between mechanical sensitivity and detonation performance is the ultimate goal in the development of new high-energy materials (HEMs). Numerous studies in the area of material design have focused on developing HEMs with high performance and low sensitivity. Unfortunately, low sensitivity of HEMs is usually accompanied by poor detonation efficiency. One of the most reliable indicators of high sensitivity towards detonation of HEM molecules is the presence of areas of strongly positive electrostatic potential over the central regions of molecular surfaces. Adjusting the electrostatic potential values in these regions provides a path to control the mechanical sensitivity of HEMs. In this work, we have studied the possible ways to fine-tune the electrostatic potential values and mechanical sensitivities of high-energy molecules using hydrogen bonds and other non-covalent interactions. Results of high-level ab initio calculations and analysis of crystallographic data showed that electrostatic interactions may significantly tune the electrostatic potential values and mechanical sensitivity of studied HEM compounds. Additionally, we have shown that tuning the electrostatic potential is particularly feasible in chelate coordination compounds, as the electrostatic properties of these molecules can be effectively modulated through careful selection of ligands and transition metals. Keywords: High-energy Materials; Ab-initio Calculations; Electrostatic Potential. Acknowledgement This research has been financially supported by the Ministry of Science, Technological Development and Innovation of Republic of Serbia (Contract numbers: 451-03136/2025-03/200026), 451-03-136/2025-03/200168 and 451-03-136/202503/200288), and it contributes to the achievement of Sustainable Development Goals 9 (Industry, Innovation, and Infrastructure) and 12 (Responsible Consumption and Production). Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 25 Tracing the molecular complexity of space through experimental– theoretical synergy in astrochemistry Heidy M. Quitián-Lara (ORCID: 0000-0002-6786-8248) Max-Planck-Institut für extraterrestrische Physik, 85748 Garching, Germany *Correspondence: heid[email protected]pg.de Abstract: Astrochemistry seeks to understand the formation and evolution of chemical species in extreme astrophysical environments. Our work focuses on the experimental study of molecules relevant to the interstellar medium through high-resolution spectroscopy and the analysis of radiation-induced fragmentation processes (QuitiánLara et al. 2018, 2025, Gerlach et al. 2022). These studies enable us to explore stability, reactivity, and possible formation pathways of compounds with astrobiological significance. However, the experimental approach is complemented and reinforced by theoretical chemistry tools, which allow us to interpret astronomical observations and predict molecular behaviour under conditions that are difficult to replicate in the laboratory. Quantum chemical calculations provide key information on molecular geometries, fragmentation energies, spectroscopic modes, and reaction mechanisms (Santos, et al. 2022, Londoño-Restrepo et al, 2025). This synergy has enabled us to thoroughly explore the reactivity of species with prebiotic potential, as well as to propose viable routes for the formation of complex molecules even in the early stages of planetary evolution. The integration of theory and experiment is fundamental to advancing our understanding of the universe's chemistry and identifying new structures as candidates for future astronomical detections Keywords: Interstellar Chemistry; Radiation-Induced Fragmentation; Quantum Chemical Modelling; Prebiotic Molecules; Spectroscopy. References Quitián-Lara, H.M., Fantuzzi, F., Oliveira, R.R., Nascimento, M.A.C., Wolff, W. and Boechat-Roberty, H.M. (2020) ‘Mon. Not. R. Astron. Soc., 499(4), pp. 6066–6083. Available at: https://doi.org/10.1093/mnras/staa3181 Santos, J.C., Fantuzzi, F., Quitián-Lara, H.M., Martins-Franco, Y., Menéndez-Delmestre, K., Boechat-Roberty, H.M. and Oliveira, R.R. (2022) ‘Mon. Not. R. Astron. Soc., 512(4), pp. 4669–4682. Available at: https://doi.org/10.1093/mnras/stac679 Gerlach, M., Preitschopf, T., Karaev, E., Quitián-Lara, H.M., Mayer, D., Bozek, J., Fischer, I. and Fink, R.F. (2022) ‘Phys. Chem. Chem. Phys., 24(27), pp. 15217–15229. Available at: https://doi.org/10.1039/D2CP02104H Londoño-Restrepo, J., Gómez, S., Quitián-Lara, H.M., Fantuzzi, F. and Restrepo, A. (2025) ‘Chem. Sci., 16(12), pp. 3051–3065. Available at: https://doi.org/10.1039/D4SC07986H Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 26 Quitián-Lara, H.M., Londoño-Restrepo, J., Gómez, S., García-González, K.V., Restrepo, A., Mason, N.J., Caselli, P., Boechat-Roberty, H.M. and Fantuzzi, F. (2025) ‘Mon. Not. R. Astron. Soc., 539(4), pp. 3778–3788. Available at: https://doi.org/10.1093/mnras/staf595 Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 27 Non-covalent sulfur interactions through the lens of quantum chemistry Ivana S. Veljković1 (ORCID: 0000-0003-0584-4053) 1University of Belgrade – Institute of Chemistry, Technology and Metallurgy – National institute of the Republic of Serbia, Njegoševa 12, 11000 Belgrade, Serbia *Correspondence: [email protected] Abstract: Among the chalcogens, sulfur stands out for the remarkable diversity of its chemical bonding and physical forms, from covalent chains and rings to polymeric structures and non-covalent interactions in molecular and crystalline systems. On the occasion of the centenary of quantum chemistry, this work highlights how modern quantum-chemical approaches, such as DFT calculations, electrostatic potential maps, NBO analysis, and potential energy surface investigation, enable a deeper understanding of sulfur-based interactions. Particular attention is given to S···S contacts that determine molecular geometry, crystal packing, and the stability of sulfur-containing systems. Examples from our studies, including quantum-chemical investigations of S···S interactions in the α-allotrope of elemental sulfur (Kretić, Medaković & Veljković, 2023), illustrate (i) preferred geometries and energetic characteristics of these contacts, (ii) their influence on molecular arrangement and crystal packing, and (iii) how theoretical analysis provides predictive insights into structures once rationalized only empirically. This work also demonstrates how quantum-chemical knowledge of sulfur interactions can be extended to the design of new materials and supramolecular assemblies. Keywords: Sulfur–Sulfur Interactions; Non-covalent bonding; Qantum-chemical Calculations. Acknowledgement This research has been financially supported by the Ministry of Science, Technological Development and Innovation of Republic of Serbia (Contract No. 451-03-136/202503/200026). References Kretić, D.S., Medaković, V.B. & Veljković, I.S. (2023). Interplay between energy and geometry of parallel-displaced interactions in S₈ dimer structures. Computational and Theoretical Chemistry, 1230, 114381. Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 28 A theoretical study of electronic and geometric properties of biologically relevant [4Fe-4S] clusters Đorđo Tintor1 (ORCID: 0009-0001-4869-9020), Maja Gruden1 (ORCID: 0000-0002-0746-5754) and Matija Zlatar2 (ORCID: 0000-0002-3809-0940) 1Faculty of Chemistry - University of Belgrade, Studentski trg 12-16, 11000 Belgrade 2Institute of Chemistry, Technology and Metallurgy, National Institute of the Republic of Serbia - University of Belgrade, Njegoševa 12, 11000, Belgrade, Serbia *Correspondence: [email protected] Abstract: Iron-sulfur clusters bound to proteins are polynuclear combinations of iron and sulfur found in all domains of life. These clusters are among the most functionally diverse cofactors found in nature, most importantly serving as catalytic centers for electron transfer reactions in processes such as photosynthesis and cellular respiration. In this work, we have investigated the electronic and geometric properties of two types of iron-sulfur clusters: [4Fe-4S] and [4Fe-4S](SCH3)4. Both models are derived from ferredoxin crystal structures (PDB: 1IQZ and PDB: 1CKU). All calculations are based on the DFT Broken Symmetry (BS) method using BP86, OPBE, and B3LYP* exchangecorrelation functionals and TZP basis set. The results indicate that the BS states are always more stable than the “high spin” states, have shorter bonds, and are antiferromagnetically coupled. This is because weak bridging ligands in polynuclear complexes, such as thiolates and sulfides, facilitate long-range, rapid electron exchange. The results all agree with experimental data obtained from various structural methods [1, 2]. Keywords: Iron-Sulfur Clusters; Density Functional Theory; Broken Symmetry. Acknowledgement Science Fund of The Republic of Serbia (#7750288) and Ministry of Science, Technological Development and Innovation of the Republic of Serbia (451-03136/2025-03/200168, 451-03-136/2025-03/200026, 451-03-136/2025-03/200288) References [1] Hagen, W.R., 2018. EPR spectroscopy of complex biological iron–sulfur systems. JBIC Journal of Biological Inorganic Chemistry, 23(4), pp.623-634. [2] Todorovic, S. and Teixeira, M., 2018. Resonance Raman spectroscopy of Fe–S proteins and their redox properties. JBIC Journal of Biological Inorganic Chemistry, 23(4), pp.647-661. Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 29 Electronic Structure and Stability of Rhodium(III)–EDTA Complexes Marko Radovanović1 (ORCID: 0000-0001-8446-7107) and Matija Zlatar2 (ORCID: 0000-00023809-0940) 1Department of Chemistry, Faculty of Science, University of Kragujevac, 34000 Kragujevac, Serbia 2 University of Belgrade – Institute of Chemistry, Technology and Metallurgy, Njegoševa 12, 11000 Belgrade *Correspondence: matija.[email protected].ac.rs Abstract: Rhodium(III) complexes with EDTA‑type ligands provide a versatile platform for exploring how chelate denticity and geometry govern structure, stability, and electronic properties. Density functional theory (DFT) calculations, combined with Energy Decomposition Analysis (EDA) and density-functional-based Ligand Field Theory (LF-DFT), were applied to a series of pentadentate and hexadentate Rhodium(III) complexes. Benchmarking against crystallographic data identified the most reliable density functional approximations for reproducing Rh–donor distances and coordination‑sphere geometries, which are critical for accurate ligand‑field splitting. LF-DFT reveals systematic correlations between chelate‑ring arrangements and d–d excitation energies, while EDA disentangles electrostatic and covalent contributions to isomer stability. The comparison of pentadentate versus hexadentate coordination highlights how subtle variations in denticity and ring size modulate excited‑state patterns and bonding interactions. These results establish quantitative links between structure and spectroscopy in Rh(III)–EDTA systems, offering a framework for interpreting experimental spectra and guiding the rational design of aminopolycarboxylate ligands and metal complexes. Keywords: Rhodium(III) Complexes; DFT; LF-DFT; Electronic Structure; Chelate Ligands. Acknowledgement This work is supported by the Serbian Ministry of Science, Technological Development and Innovation (451–03–136/2025–03/200026) and the Science Fund of the Republic of Serbia (#7750288). THE APPLICATION OF QUANTUM SCIENCE TO OUR WIDER UNDERSTANDING OF PHENOMENA, INCLUDING RADIATION SCIENCES Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 31 Quantum diffraction and interference phenomena in atomic processes Nenad Simonović1 (ORCID: 0000-0002-3319-9904) 1Institute of Physics Belgrade, Pregrevica 118, 11080 Belgrade, Serbia Abstract: Diffraction of matter particles on various targets, such as lattices, slit shields, other particles, etc., and study of the resulting interference patterns were key experiments that established the quantum-wave nature of matter. Beginning with the Davison-Germer experiment in 1927, which confirmed the wave properties of electrons, experiments of this type have been performed throughout the century-long history of Quantum Mechanics. To demonstrate the universality of quantum principles, of particular importance were the experiments that confirmed the wave nature of very massive particles, such as the fullerene molecule C60, and more recently, molecules consisting of several thousand atoms [1]. On the other hand, the structure of large particles like C60 have been investigated using electron scattering on these molecules as spherical diffraction lattices [2]. In this lecture we will present the results of experimental and theoretical research on several problems on this topic, in which the Laboratory for Atomic Collision Processes of the Institute of Physics Belgrade was involved in recent years. Among them will be presented the results of research on the diffraction of a beam of atoms on a crystal lattice at grazing incident angles [3], diffraction of electrons on atomic particles [4], as well as specific cases of superposition of electron wave packets known as dynamic and exchange interference [5,6]. Keywords: Quantum Mechanics; Diffraction; Interference; Atomic Processes. References [1] M. Arndt, O. Nairz, J. Voss-Andreae, C. Keller, G. van der Zouw, and A. Zeilinger, Nature (London) 401, 680-682 (1999); Y. Y. Fein, P. Geyer, P. Zwick, F. Kiałka, S. Pedalino, M. Mayor, S. Gerlich and M. Arndt, Nature Physics 15, 1242–1245 (2019). [2] R. Aiswarya, R. Shaik, J. Jose, H. R. Varma, and H. S. Chakraborty, Phys. Rev. Lett. 133, 033002 (2024). [3] F. Aigner, N. Simonović, B. Solleder, L. Wirtz and J. Burgdörfer, Phys. Rev. Lett. 101, 253201 (2008). [4] R. Aiswarya, J. Jose, N. Simonović, B. P. Marinković, H. S. Chakraborty, arXiv: 2507.04466. [5] N. S. Simonović, D. B. Popović, A. Bunjac, Atoms 11, 20 (2023). [6] B. Paripasa, J. Jureta, B. Palasthya, B. Marinković, G. Pszota, J. El. Spectr. 225, 10 (2018). Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 32 The Enduring Mystery of Wigner’s Friend Igor Salom1 (ORCID: 0000-0002-1119-730X) 1Institute of Physics Belgrade, Pregrevica 118, Belgrade Abstract: The enormous success of quantum theory over the past century often makes us forget that Feynman’s famous remark, “nobody understands quantum mechanics”, is probably as valid today as ever. While experimental violations of Bell’s inequalities have forced us to abandon the hope of ever recovering a (local) mechanistic picture of the universe, the Wigner’s friend conundrum highlights what is perhaps the deepest yet unresolved problem at the foundations of quantum science. Exemplifying the seeming inconsistency at the very heart of its mathematical formulation, this quantum thought experiment is one of the rare cases where even a consensus about the outcome is lacking among experts. We will revisit this thought experiment and some of its recent developments, discussing both the known possible resolutions and advocating some novel ones. Keywords: Wigner’s Friend Paradox; Measurement Problem; Interpretations of Quantum Mechanics. Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 33 Comparative analysis of machine learning algorithm results in predicting the probability of rectal tumor presence Aleksandra Bibić¹, Ivana Mišković², Stevan Pecić³, Mladen Marinković², and Edib Dobardžić³ 1Faculty of Medicine, University of Belgrade, Belgrade, Serbia 2Clinic for Radiation Oncology, Institute for Oncology and Radiology, Belgrade, Serbia 3Faculty of Physics, University of Belgrade, Belgrade, Serbia *Correspondence: [email protected] Abstract: This study examines the application possibilities of machine learning (ML) algorithms in the analysis of computed tomography (CT) scans aimed at diagnosing tumor changes in specific organs. The focus of this study is on detecting tumor tissue in the rectal area. The plan is to train a model that will recognize and identify the tumor location using exclusively CT scans, without relying on magnetic resonance imaging. The long-term goal is the development and validation of algorithms that could be integrated into medical devices for automatic identification of tumor tissue, where the device would display the probability that the tissue is affected by a tumor. The study included data from 140 patients. Only those slices depicting the rectal region were selected, resulting in approximately 3,600 images suitable for analysis. A set of the most relevant features was extracted from the images, and a table was created for training and testing multiple ML algorithms. In addition to classical ML algorithms, neural networks were trained to compare performance and explore the potential of deep learning in tumor detection. Models were trained on the same feature set with a training and testing split. Evaluation focused particularly on sensitivity and specificity parameters, which are critical in medical diagnostics. The best result on the available dataset was achieved using the support vector machines algorithm, which reached over 80\% accuracy in tumor area detection. Neural networks demonstrated potential for higher sensitivity, with a need for further model architecture tuning to improve specificity. This approach can contribute to more efficient diagnostics, resource and time savings for physicians, as well as enabling more precise therapy planning and a personalized patient approach. Keywords: Computed Tomography; Machine Learning; Rectal Carcinoma. Acknowledgement MM is supported by the Horizon Europe STEPUPIORS Project (HORIZON-WIDERA2021-ACCESS-03, European Commission, Agreement No. 101079217) and the Ministry of Science, Technological Development and Innovation of the Republic of Serbia (Agreement No. 451-03-136/2025-03/200043). Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 40 AI-Generated Framework for Machine Learning in Plasma Diagnostics: A Meta-Demonstration of Artificial Intelligence in Atomic Spectroscopy Ivan Belča1 (ORCICD: 0000-0001-6124-5333) 1University of Belgrade Faculty of Physics Abstract: In this work, we have presented some of the excellent possibilities of using AI/ML in the physical sciences, with special reference to atomic and molecular spectroscopy. This paper is a meta-demonstration of sorts: At our request and under our supervision, AI (Claude, Anthropic) generated a complete research framework that analyzes the current state of AI/ML applications in spectroscopy and implements a fully functional example - from physical simulations to the use of machine learning. For a demonstration, we chose plasma diagnostics - an area that is very important for collisional physics and atmospheric sciences. Using AI, we developed: (i) a physicsbased argon plasma emission spectrum simulator incorporating collisional-radiative models, NIST atomic data, and electron impact excitation kinetics, generating 2,000 synthetic spectra across electron temperature ranges of 1-5 eV and densities of 10¹⁶10¹⁸ m⁻³ (Srikar, 2024); and (ii) deep neural networks, random forests, multi-layer perceptrons and XGBoost trained to perform inverse diagnostics—predicting plasma parameters from optical emission spectra. The work demonstrates AI's transformative potential in spectroscopy through a recursive approach: AI analyzing AI applications, AI generating physical simulations, and AI building diagnostic tools. Keywords: Artificial Intelligence; Machine Learning; Plasma Diagnostics; Optical Emission Spectroscopy; Collisional-radiative Model. References [1] Srikar, P.S.N.S.R. at al.,(2024), Accelerated real-time plasma diagnostics: Integrating argon collisional-radiative model with machine learning methods, Nucl. Instrum. Methods Phys. Res. B [2] Wang, YF. ,Zhu, X.M.,(2024), Development of optical emission spectroscopy method with neural network, model, J. Appl. Phys. 136, 243302 [3]Trieschmann, J. at al, (2023), Review: Machine learning for advancing lowtemperature plasma modeling and simulation, J. Micro/Nanopattern. Mats. Metro. 22(4) 041504 [4] Kramida, A. et al.,(2024), NIST Atomic Spectra Database (ver. 5.11), National Institute of Standards and Technology [5] Carleo, G. et al.,(2019), Machine learning and the physical sciences, Rev. Mod. Phys. 91, 045002 Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 41 The Role of Small Molecules in Astrophysics: From Collisions to Radiation Vladimir Srećković1 (ORCID: 0000-0001-7938-5748) 1Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, Belgrade, Serbia *Correspondence: vlad[email protected] Abstract: Atomic and molecular collisions, together with radiative processes, play a fundamental role in shaping the diverse environments of our universe. These interactions govern molecular energy transfer, excitation, and de-excitation, thereby influencing the spectra of numerous astrophysical sources such as planetary atmospheres, interstellar clouds, and circumstellar envelopes (see, e.g., Sreckovic et al. 2022). Reliable data and comprehensive databases on atomic and molecular processes have become increasingly vital for the development of models and simulations of complex physical and chemical systems, as well as for interpreting observational and experimental results across multiple scientific domains (Vujcic et al. 2023). Such data are also essential for a range of applications, including modeling the non-local thermal equilibrium chemistry of the early universe, the solar atmosphere, and white dwarf environments. Advancing this field requires the development of new methodologies and the refinement of existing models to incorporate a broader range of processes and utilize more precise datasets compatible with modern computational tools. For environments such as laboratory plasmas, planetary atmospheres, and the ionosphere, the primary objective is to determine accurate cross sections and rate coefficients for key collisional and radiative processes (Albert et al. 2020). In this work, we present and discuss such data, contributing to the ongoing effort to enhance the accuracy and applicability of atomic and molecular databases for astrophysical and plasma research. Keywords: Atomic and Molecular Collisions; Radiative Processes; Cross Sections and Rate Coefficients; Astrophysical Modeling and Plasma environments. Acknowledgement We gratefully acknowledge the networking opportunities provided by COST Actions CA21101 (COSY) and CA22133 (PLANETS), supported by COST (European Cooperation in Science and Technology). The authors also recognize the support of the Institute of Physics Belgrade. V.A.S. acknowledges the support of the Science Fund of the Republic of Serbia through Grant No. 6821, Atoms and (bio)molecules – dynamics and collisional processes on short time scales (ATMOLCOL). References Albert, D., Antony, B. K., Ba, Y. A., ... & Zwölf, C. M. : 2020, Atoms, 8(4), 76. Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 42 Sreckovic, V. A., Ignjatovic, L. M., Kolarski, A., Mijic, Z. R., Dimitrijevic, M. S., & Vujcic, V. : 2022, Data, 7, 129. Vujčić, V., Marinković, B. P., Srećković, V. A., Tošić, S., Jevremović, D., Ignjatović, L. M., ... & Mason, N. J. : 2023, Phys. Chem. Chem. Phys., 25(40), 26972-26985. Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 43 Development and applications of Machine learning and Artificial Intelligence in High energy physics and Nuclear physics Dimitrije Maletic1 (ORCID: 0000-0002-9163-6703) 1 Institute of Physics, University of Belgrade, Pregrevica 118, Belgrade, Serbia Abstract: I'm presenting a view on reach and development of Machine learning and Artificial Intelligence in High energy physics and Nuclear physics, with my 20 years of experience in the field. The most important research and development milestones and most important applications, both for widely popular use, and for most interesting physics experiments are discussed. AI tools used by beginners, and tools for advanced users are presented and discussed. Furthermore, most important elements in using, and development of your own AI application are presented and explained in sufficient details. Lastly, I'm presenting several examples from elementary particle physics and nuclear physics which I was developing or working on. Keywords: Machine learning, Artificial Intelligence , AI applications Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 44 Understanding Artificial Intelligence: Navigating Through Physical and Virtual Worlds Vladimir M. Petrović1 (ORCID: 0000-0002-9089-2246) 1Institute of Physics Belgrade (University of Belgrade), Pregrevica 118, Belgrade, Serbia *Correspondence: [email protected] Abstract: The present moment in human history is marked by the rapid and farreaching advancements of artificial intelligence (AI) and related technologies. Applications of AI-based research now extend across nearly every domain of science, industry, and daily life. From predictive modeling to image recognition, from large language models to robotics, from game AI to real-time industrial applications – AI research is covering an extensive array of topics. Looking at the past, one could notice that in the very foundations of AI research lies the desire to emulate human intellectual capabilities, therefore making the pursuit of intelligent and autonomous agent behavior a central topic of the entire field. This desire to replicate human capabilities can be traced back in history, even before AI was established as a scientific field. As a result, it is not surprising that both general and academic non-expert audiences sometimes misinterpret the capabilities of advanced AI systems, attributing to them a human-level intelligence. Additionally, especially bearing in mind the present moment, a non-expert audience sometimes perceives and uses AI systems as black-box solutions, often without a clear understanding of their underlying principles and mechanisms. In this invited talk, we will critically examine these issues by navigating through physical and virtual world challenges, thereby elucidating the origins and present capacities of machine intelligence. This will be achieved through a multidisciplinary approach, dealing not only with AI algorithms but also with human evolution, physical and virtual embodiment, and other topics of interest. Ultimately, we will examine the current boundaries of AI development and discuss the implications for achieving human-like AI. This will include exploring both the real world and immersive virtual environments as AI research platforms. Keywords: Artificial Intelligence; Machine Learning; Human-Level AI; Embodiment; Virtual Worlds. Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 45 Reproducibility as a Foundation for Reliable Computational Quantum Chemistry Data Matija Zlatar1, 2 (ORCID: 0000-0002-3809-0940) 1University of Belgrade – Institute of Chemistry, Technology and Metallurgy, Njegoševa 12, 11000 Belgrade, Serbia 2Serbian Reproducibility Network *Correspondence: matija.[email protected].ac.rs Abstract: Artificial intelligence (AI) and machine learning (ML) are transforming spectroscopy and chemical physics, yet their success depends on the availability of reliable and reproducible data. Computational quantum chemistry provides a powerful source of such data when workflows are transparent, systematically benchmarked, and rigorously documented. Reproducible protocols ensure that calculated spectra and molecular properties can be trusted, reused, and integrated into AI/ML models without hidden biases and inconsistencies. By embedding reproducibility into computational practice, quantum chemical results become trustworthy resources that can be directly reused, compared, and expanded within machine learning frameworks. Beyond technical rigor, reproducibility is framed as a driver of equity and participation: by lowering barriers to entry, reproducible workflows empower broader engagement in global science. Reproducibility is not only a methodological necessity but also a cultural transformation, aligning with open science principles and the UN Sustainable Development Goals. Keywords: Reproducibility; Computational Quantum Chemistry; Reliable Data; AI/ML. Acknowledgement This work is supported by the Serbian Ministry of Science, Technological Development and Innovation (451–03–136/2025–03/200026) and the Science Fund of the Republic of Serbia (#7750288). Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 46 Author Index Author Page Adnan Naja 3 Ahmad Ossman 3 Aleksandra Bibić 33 Andjelka Kovačević (ORCID: 0000-0001-5139-1978) 4 Andrew Cassidy 11 Ashutosh Yadav 13 Bassem Hmouda 3 Bobby Antony (ORCID: 0000-0003-2073-9681) 13 Bratislav M. Obradović (ORCID: 0000-0002-3221-7779) 16 Bratislav P. Marinković (ORCID: 0000-0002-6904-6360) 8, 9, 19 Cauê P. Souza (ORCID: 0000-0001-5545-004X) 23 Courtney Ennis (ORCID: 0000-0003-1774-8982) 6 Danijela Kretić (ORCID: 0000-0002-1382-8785) 24 Danko Bošnjaković (ORCID: 0000-0002-2725-5287) 34 David Field (ORCID: 0000-0002-2049-4189) 11 Dimitrije Maletic (ORCID: 0000-0002-9163-6703) 43 Đorđo Tintor (ORCID: 0009-0001-4869-9020) 28 Duncan V. Mifsud (ORCID: 0000-0002-0379-354X) 23 Dušan Veljković (ORCID: 0000-0002-1382-8785) 24 Edib Dobardžić 33 Ena Todorovic 7 Felipe Fantuzzi (ORCID: 0000-0002-8200-8262) 21, 23 Francisco Blanco 9 Ghassan Ragheb 3 Goran B. Poparić (ORCID: 0000-0002-6794-4976) 12 Gustavo Garcia (ORCID: 0000-0003-4033-4518) 9 Heidy M. Quitián-Lara (ORCID: 0000-0002-6786-8248) 25 Helen E. Maynard-Casely (ORCID: 0000-0001-6364-9665) 6 Hristina Delibašić (ORCID: 0000-0002-8391-4179] 19 Igor Petrovic (ORCID: 0000-0002-8546-3623) 36 Igor Salom (ORCID: 0000-0002-1119-730X) 32 Ilija Simonović (ORCID: 0000-0001-6704-9042) 34 Ivan Belča (ORCICD: 0000-0001-6124-5333) 40 Ivana Mišković 33 Ivana S. Veljković (ORCID: 0000-0003-0584-4053) 24, 27 Jasmina Jeknic-Dugic (ORCID: 0000-0002-4905-6457) 36 Jelena B. Maljković (ORCID: 0000-0001-9176-2673) 8, 9, 19 Jelena Vukalović (ORCID: 0000-0001-6704-1905) 9, 19 Jozo J. Jureta 8 Juraj Fedor (ORCID: 0000-0002-4549-9680) 14 Larissa Lopes Cavalcante (ORCID: 0000-0002-4047-7220) 6 Lars Borchert (ORCID: 0000-0002-6421-891X) 23 Mahmoud Israel 3 Maja Gruden (ORCID: 0000-0002-0746-5754) 28 Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025 47 Maria Benedetta Casu (ORCID: 0000-0002-5659-7040) 37 Marko Radovanović (ORCID: 0000-0001-8446-7107) 29 Matija Zlatar (ORCID: 0000-0002-3809-0940) 23, 28, 29, 45 Milan Milovanović (ORCID: 0000-0001-6409-4534) 7 Miloš Ranković (ORCID: 0000-0003-1317-0132) 14 Miroljub Dugic (ORCID: 0000-0002-4493-6009) 36 Mladen Marinković 33 Momir Arsenijevic (ORCID: 0000-0003-4622-642X) 36 Nenad Simonović (ORCID: 0000-0002-3319-9904) 31 Nevena Puač (ORCID: 0000-0003-1142-8494) 17 Nigel J. Mason (ORCID: 0000-0002-4468-8324) 2, 23 Nikola Cvetanović (ORCID: 0000-0002-9806-3469) 16 Nikola Škoro (ORCID: 0000-0002-0254-8008) 17 Olivera Jovanović (ORCID: 0000-0003-2633-1580) 17 Pamir Nag (ORCID: 0000-0002-1530-6104) 14 Sanja Tošić (ORCID: 0000-0003-4613-5659) 19 Saša Dujko (ORCID: 0000-0002-4544-9106) 34 Sergio Ioppolo (ORCID: 0000-0002-2271-1781) 23 Stevan Pecić 33 Sudhanshu Arya 13 Tijana Cepenjor 7 Tomoyuki Murakami (ORCID: 0000-0003-0618-2055) 17 Violeta Petrović (ORCID: 0000-0002-7865-523X) 19 Vladimir M. Petrović (ORCID: 0000-0002-9089-2246) 44 Vladimir Srećković (ORCID: 0000-0001-7938-5748) 19, 41 Centennial of Quantum Theory: Progress in Atomic and Molecular Structure – CEQPAS 2025