Laboratory investigations on non-thermal solid-gas exchanges in cold and illuminated regions of interstellar medium

Jean-Hugues Fillion LABORATORY INVESTIGATIONS ON NON-THERMAL SOLID-GAS EXCHANGES IN COLD AND ILLUMINATED REGIONS OF INTERSTELLAR MEDIUM PIXyES Water in the Universe, Oléron Island, 1-3 October 2025 Cold regions of the interstellar medium ICE MANTLE : molecular reservoir ▪H2O , ▪CO, CO2, CH4, NH3, OCN-, ▪HCOOH, H2CO ▪CH3OH ▪other organics 0,01-0,5 µm Meinert 2011 H2O/H2≤ 4 ×10-4 Boogert 2015 Öberg 2016 Meinert +2011 Main reservoir of molecular matter Mostly H2O, CO, CO2, CH3OH, NH3, CH4… High molecular richness even in cold regions… Solid Phase Gas Phase In frontier regions (PDR): H2O, CO, CO2, CH3OH, H2CO, CH3CN… Boogert+2015, McClure+2023, Sturm+2023 In prestellar cores: CH3OH, CH3CN, HCOOH, HCOOCH3… In disks: H2O, CO, CH3CN in many sources, CH3OH, HCOOH in TW Hydrae (Guzman+ 2011, 2013, 2014 ; Gratier+ 2013, Putaud+ 2019…) (Vastel+ 2014, Bacmann+ 2012, Jimenez-Serra+ 2016… ) (Willacy&Langer 2000, Hogerheidje+ 2011, Bergner+2018, Carney+2019, Walsh+2016, Favre+2018, Loomis+2018) Motivations: non-thermal desorption in the cold ISM Main reservoir of molecular matter Mostly H2O, CO, CO2, CH3OH, NH3, CH4… High molecular richness even in cold regions… Solid Phase Gas Phase In frontier regions (PDR): H2O, CO, CO2, CH3OH, H2CO, CH3CN… Boogert+2015, McClure+2023, Sturm+2023 In prestellar cores: CH3OH, CH3CN, HCOOH, HCOOCH3… In disks: H2O, CO, CH3CN in many sources, CH3OH, HCOOH in TW Hydrae (Guzman+ 2011, 2013, 2014 ; Gratier+ 2013, Putaud+ 2019…) (Vastel+ 2014, Bacmann+ 2012, Jimenez-Serra+ 2016… ) (Willacy&Langer 2000, Hogerheidje+ 2011, Bergner+2018, Carney+2019, Walsh+2016, Favre+2018, Loomis+2018) Motivations: non-thermal desorption in the cold ISM Need for non-thermal desorption processes to maintain molecular abundances in the gas phase Inner and outer regions of molecular clouds (Hollenbach 2009) Atmospheres of Icy satellites in the outer solar system UV Photons : H Ly-a Outer parts of protostellar envelopes (Mottram 2012, Notsu 2021) Prestellar cores (Caselli 2012) cosmic-ray-induced FUV field Protoplanetary disks (Dominik 2005, Bergin 2014, Walsh 2010, Salinas 2016) B68 UV and X-ray photons Henning & Semenov 2013 Horsehead Photodesorption : an universal phenomenon Enceladus Molecule Ice Desorbed species ref CO Pure & withN2CO Fayolle+2011; MunozCaro+2010, 2016, Oberg+2009, Bertin+2013, Paardekooper+2016… H2O & D2O pure (in different morphologies) H2O, OH, O2, H2Westley+1995, Oberg+2009, Cruz-Diaz+2018, Bulak+2022, Fillion+2022 CO2Pure CO2, CO, O2, CO3Oberg+2009, Fillion+2014, Martin-Domenech+2015, Sie+2019 N2Pure & with CO & with CO2N2Fayolle+2013, Bertin+2013, Carrascosa+2019 NH3Pure NH3, N2Martin-Domenech+2018, Torres-Diaz+2024 CH4 Pure & with CO & with H2 O CH4, CO, H2CO Martin-Domenech+2016, Dupuy+2017, Bulak+2020 O2Pure O2Fayolle+2013, Zheng+2014 NO Pure NO Dupuy+2017 H2CO Pure & withCO H2CO, H2, CO Féraud+2019 Simple molecules CH3OH Pure & with CO CH3OH, CH3O, H2CO, CH3, OH, CO Oberg+2009, Bertin+2016, Cruz-Diaz+2016 HCOOH Pure, with CO, with H2OHCOOH, H2CO, HCO, CO2, CO, H2OBertin+2023 HCOOCH3Pure, with CO, with H2OHCOOCH3, H3CO, H2 CO, HCO, CH3, O2, CO2, CO, H2O Bertin+2023 CH3CN Pure, with CO, with H2OCH3CN, HC2N, HCN, CN, CH3Basalgète+2021, Bulak+2021 Small organics •Yields mostly extracted from pure ices State of the experimental studies of UV photodesorption: species & yields Molecule Ice Desorbed species ref CO Pure & withN2CO Fayolle+2011; MunozCaro+2010, 2016, Oberg+2009, Bertin+2013, Paardekooper+2016… H2O & D2O pure (in different morphologies) H2O, OH, O2, H2Westley+1995, Oberg+2009, Cruz-Diaz+2018, Bulak+2022, Fillion+2022 CO2Pure CO2, CO, O2, CO3Oberg+2009, Fillion+2014, Martin-Domenech+2015, Sie+2019 N2Pure & with CO & with CO2N2Fayolle+2013, Bertin+2013, Carrascosa+2019 NH3Pure NH3, N2Martin-Domenech+2018, Torres-Diaz+2024 CH4 Pure & with CO & with H2 O CH4, CO, H2CO Martin-Domenech+2016, Dupuy+2017, Bulak+2020 O2Pure O2Fayolle+2013, Zheng+2014 NO Pure NO Dupuy+2017 H2CO Pure & withCO H2CO, H2, CO Féraud+2019 Simple molecules CH3OH Pure & with CO CH3OH, CH3O, H2CO, CH3, OH, CO Oberg+2009, Bertin+2016, Cruz-Diaz+2016 HCOOH Pure, with CO, with H2OHCOOH, H2CO, HCO, CO2, CO, H2OBertin+2023 HCOOCH3Pure, with CO, with H2OHCOOCH3, H3CO, H2 CO, HCO, CH3, O2, CO2, CO, H2O Bertin+2023 CH3CN Pure, with CO, with H2OCH3CN, HC2N, HCN, CN, CH3Basalgète+2021, Bulak+2021 Small organics •Yields mostly extracted from pure ices State of the experimental studies of UV photodesorption: species & yields Molecule Ice Desorbed species ref CO Pure & withN2CO Fayolle+2011; MunozCaro+2010, 2016, Oberg+2009, Bertin+2013, Paardekooper+2016… H2O & D2O pure (in different morphologies) H2O, OH, O2, H2Westley+1995, Oberg+2009, Cruz-Diaz+2018, Bulak+2022, Fillion+2022 CO2Pure CO2, CO, O2, CO3Oberg+2009, Fillion+2014, Martin-Domenech+2015, Sie+2019 N2Pure & with CO & with CO2N2Fayolle+2013, Bertin+2013, Carrascosa+2019 NH3Pure NH3, N2Martin-Domenech+2018, Torres-Diaz+2024 CH4 Pure & with CO & with H2 O CH4, CO, H2CO Martin-Domenech+2016, Dupuy+2017, Bulak+2020 O2Pure O2Fayolle+2013, Zheng+2014 NO Pure NO Dupuy+2017 H2CO Pure & withCO H2CO, H2, CO Féraud+2019 Simple molecules CH3OH Pure & with CO CH3OH, CH3O, H2CO, CH3, OH, CO Oberg+2009, Bertin+2016, Cruz-Diaz+2016 HCOOH Pure, with CO, with H2OHCOOH, H2CO, HCO, CO2, CO, H2OBertin+2023 HCOOCH3Pure, with CO, with H2OHCOOCH3, H3CO, H2 CO, HCO, CH3, O2, CO2, CO, H2O Bertin+2023 CH3CN Pure, with CO, with H2OCH3CN, HC2N, HCN, CN, CH3Basalgète+2021, Bulak+2021 Small organics •Yields mostly extracted from pure ices State of the experimental studies of UV photodesorption: species & yields •Photochemistry coupled to the desorption 7 8 9 10 11 12 13 0,0 2,0x10-2 4,0x10-2 6,0x10-2 Incident Photon Wavelength (nm) Photodesorption Yield (ejected molecule/incident photon) Incident Photon Energy (eV) 170160 150 140 130 120 110 100 90 A 1Π(v’)- X1Σ+(v =0) B-X , C-X, E-X Experimental Strategy Synchrotron Radiation - Tunable over a wide spectral range -1012–1013 photons ( 30-40 meV bandwith) - Light polarisation (linear, Cicular etc) - Pulsed (360 MHz @24 paquets) Photdesorption Yields 𝑌(Eph) Pulsed VUV LASER - Tunable over a narrow spectral range (8-10 eV) -108–109photons/pulse (0.02 meV bandwith @10 eV) - Light polarisation (linear, Cicular) - Pulsed (10 Hz) Kinetics and Internal energy Ԧ𝑝 v Ԧ 𝐽 7 8 9 10 11 12 13 14 2x10-4 4x10-4 6x10-4 8x10-4 H2O D2O Desorption Yield (molecules/photon) Photon energy (eV) Fillion et al. A&A 2021 (under review) 15 K A very strong isotopic effect ~ 6-9 between H2O and D2O Water photodesorption : D2O vs H2O Hydroxyl radicals behave differently No temperature dependence 7 8 9 10 11 12 13 14 0 2x10-4 4x10-4 6x10-4 8x10-4 1x10-3 OD OH Desorption yield (molecule/photon) Photon energy (eV) 177.1 155.0 137.8 124.0 112.7 103.3 95.4 88.6 nm Fillion+2014 Experimental Yields are in very good agreement with Molecular Dynamics simulations Comparison with MD simulations 60% OD 40% D2O 66% OH 34% H2O >86% %88 12% <12% < 88 % OD D2OOH H2O MD simulations Experiment Available Kinetic Energy OD 0.275 eV OH 0.142 eV Miyazaki et al. 2020 Tsuge and Watanabe 2021 H2O H + OH D2O D + OD Photodissociation < Ebinding Hexagonal ice Amorphous ice OH OD 9 eV S. Andersson and E.F. van Dishoeck A&A 2008 Chemical recombination and isotopic effect H2O OH + H ✓H and OH recombine and desorb as H2O ✓Recombination mechanism enhanced for H2O D2O OD +D Photodissociation Photodissociation Most OD leaves the surface Most OH move on the surface Ab initio Calculations + Experiments Nishi+1984, DeSimone+2013 (Classical) MD Simulations The Multiple desorption mechanisms of intact water Chemical Recombination and desorption Collision with fast H atoms « kick-out » Repulsion of the exited H2O « Dipole reversal» Andersson+ 2008, 2011, …. Arasa+2010, Crouse+2015, … DIET Surface chemistry Outline •Vacuum-UV Photodesorption of pure H2O samples •H2Oand D2O ASW : isotopic effect •Binary systems: kick-out mechanism •Soft X-ray Photodesorption ( O K-edge) •H2O photodesorption •CH3OH mixed with CO or H2O •Vacuum-UV Photodesorption binary samples •CO2, CO, O2photodesorption •H2O, OH, H2photodesorption •Other oroganics Photodesorption from binary systems H2O -100 ML Compact Amorphous Water ice Ar, 1 ML T=15 K ✓Indirect photodesorption ✓Yield increases with photon energy Dupuy et al. PRL 2021 0.0E+0 1.0E-3 2.0E-3 3.0E-3 4.0E-3 5.0E-3 0.0E+0 2.0E-4 4.0E-4 6.0E-4 8.0E-4 7.0 7.5 8.0 8.5 9.0 9.5 10.0 0.0E+0 2.0E-3 4.0E-3 6.0E-3 Photodesorption yield (mol/photon) CO 1 MLeq on H2O N2 1 MLeq on H2O Kr 1 MLeq on H2O Photon energy (eV) Pure CO (x 1/19) Indirect photodesorption from H2O/D2O Dupuy et al. PRL 2021 D2O is more efficient than H2O Dupuy et al. PRL 2021 Summary of the investigated systems Yields measured at 9 eV Mass effect Y(CO)> Y(N2) > Y(Ar)> Y(Kr) Collision Induced Desorption (« kick-out ») ✓Hard Sphere Model 0100 200 300 400 500 600 700 800 0.00 0.03 0.07 0.10 0.14 0.17 0.21 0.24 0.28 0.0E+0 1.0E-3 2.0E-3 3.0E-3 4.0E-3 5.0E-3 N2/H2O CO/H2ON2/D2O CO/D2O Ar/D2O Ar/H2O Kr/D2O Indirect photodesorption yield (mol/photon) Transferred kinetic energy in an H/D collision (meV) Kr/H2O Desorption probability model Fraction of transferred kinetic energy in an H/D collision Collision Induced Desorption (« kick-out ») ✓Hard Sphere Model ✓Desorption probability Fredon et al. 2017 Fredon et al. 2018 Dupuy et al. PRL 2021 Scenarios for the photodesorption from binary layers Photo Energy 10 eV CO2 coverage H2OOH HCO H3CO H2CO H2 Scenarios for the photodesorption from binary layers Photo Energy 10 eV CO2 coverage H2 H2OOH HCO H3CO H2CO H2 Scenarios for the photodesorption from binary layers Photo Energy 10 eV CO2 coverage H2 H2OOH HCO H3CO H2CO H2 H2O O2 CO CO2 OH O2 HCO H2CO H3CO Conclusion ❑Pure H2O samples: mutiple phodesorption mechanism ✓Surface photochemistry (isotopic effect) ✓kick-out mechanism ❑Binary samples H2O/CO2 ✓Two contributions : H2O-dominated / CO2-dominated ✓New hydrogenation processes ✓Photodesorption of small organics from simple ices Acknowledgments PIXyES: Photodesorption Induced by UV-X-rays and Electrons on Surfaces A. Hacquard, R. Basalgète, G. Féraud, L. Philippe, P. Jeseck, X. Michaut, J.-H. Fillion M. Monnerville, S. Del Fré, A. Rivero Santamaria, D. Duflot A. Lafosse, D. Torres-Díaz, L. Amiaud Feb. 2020 –Jan. 2025 M. Bertin