Theoretical Chemistry of Atmospheric Processes

  Ci a ion: Viegas, L.P. Theo e ical Chemis y o A mosphe ic P ocesses. A mosphe e 2022,13, 309. h ps:// doi.o g/10.3390/a mos13020309 Recei ed: 7 Feb ua y 2022 Accep ed: 10 Feb ua y 2022 Published: 12 Feb ua y 2022 Publishe ’s No e: MDPI s ays neu al wi h ega d o ju isdic ional claims in published maps and ins i u ional a il- ia ions. Copy igh : © 2022 by he au ho . Licensee MDPI, Basel, Swi ze land. This a icle is an open access a icle dis ibu ed unde he e ms and condi ions o he C ea i e Commons A ibu ion (CC BY) license (h ps:// c ea i ecommons.o g/licenses/by/ 4.0/). a mosphe e Edi o ial Theo e ical Chemis y o A mosphe ic P ocesses Luís Ped o Viegas Coimb a Chemis y Cen e -Ins i u e o Molecula Sciences, Uni e si y o Coimb a, 3004-531 Coimb a, Po ugal; [email p o ec ed] A mosphe ic chemis y occu s wi hin a ab ic o p o oundly complica ed dynamics h ough se e al a mosphe ic laye s. Unde s anding he unde lying heo e ical de ails o he a mosphe e’s chemical p ocesses is o undamen al impo ance, no only o assis he in e p e a ion o obse a ional/ ield and labo a o y measu emen s, bu also o con ibu e o he building blocks o heo e ical models wi h good p edic i e capabili ies. P io i y socie al challenges such as clima e change mi iga ion o cou se bene i om he knowledge esul ing om a mosphe ic chemis y esea ch which guides he necessa y policies o mi iga e he haza dous consequences o clima e change. In his Special Issue on “Theo e ical Chemis y o A mosphe ic P ocesses”, i e o iginal esea ch a icles epo ecen indings desc ibing he modelling o eac ions and p ocesses aking place in he a mosphe e, while a e iew inishes his Special Issue. The esea ch a icles span a a ie y o subjec s: N 2 + H 2 eac i e collisions [ 1 ], sul u ic acid-base clus e o ma ion [ 2 ], he eac ion mechanism o e hylbenzene-OH adduc wi h O 2 and NO 2 [ 3 ], kine ics o eac ions o ozone wi h halogen a oms (Cl, B and I) [ 4 ] and an empi ical model o ozone concen a ion highligh ing he oles o isop ene and mono e penes [ 5 ]. Finally, a e iew pape p esen s us a p oposal o a p og amme o esea ch o heo e ical chemis y whe e a mosphe ic u bulence is p ope ly discussed [6]. This edi o ial p o ides highligh s o such a icles. In he i s piece, Ga ido and Balles e [ 1 ] pe o m a heo e ical s udy o he N 2 ( υ ’) + H 2 ( υ ”) eac i e collisions o high ib a ional and ansla ional ene gies, which a e he exis ing condi ions in he shock wa e laye s c ea ed by ela i ely la ge me eo i es, een y space ehicles, and hype sonic missiles. The au ho s ind ha he main p oduc o he eac ion is N 2 + H + H wi h he ib a ional ene gy in he H 2 eac an ha ing a de e minan ole in he dissocia ion p ocess. The con e sion o a conside able quan i y o molecula hyd ogen in a omic hyd ogen is hen iewed as ha ing po en ial signi ican impac in impo an a mosphe ic eac ions whe e a omic hyd ogen is a eac an . Howe e , he lack o expe imen al da a o he high empe a u es conside ed in his wo k hinde s a di ec compa ison wi h he heo e ical esul s. In he second pape , Xie and Elm [ 2 ] s udy he o ma ion o a mosphe ic clus e s, which a e belie ed o be he ini ial s ep o a mosphe ic ae osol pa icle o ma ion. The la e a e known o ha e an impac on global clima e and o also ac as seeds in cloud o ma ion. Sul u ic acid (SA) is known o be an essen ial pa o his p ocess, and in his esea ch pape , he au ho s in es iga e po en ial syne gis ic e ec s be ween di e en bases capable o enhancing SA-base clus e o ma ion. Thei quan um chemical s udies show ha he e is a syne gis ic e ec be ween he h ee s udied bases p esen in hese SA-base clus e s. Hence, o SA-base clus e s, i is e y likely ha mixed base clus e s wi h h ee, o po en ially mo e bases a e in ol ed in he clus e o ma ion pa hways. The e o e, he au ho s sugges ha simila in es iga ions should be ex ended o la ge sys ems o allow de ailed clus e kine ics modelling. In he hi d piece, Zhang e al. [ 3 ] use densi y unc ional heo y and con en ional ansi ion s a e heo y o s udy he eac ion mechanism and kine ics o he mos s able e hylbenzene-OH adduc (EB-O ho) wi h O 2 and NO 2 . The au ho s sugges nine possible A mosphe e 2022,13, 309. h ps://doi.o g/10.3390/a mos13020309 h ps://www.mdpi.com/jou nal/a mosphe e A mosphe e 2022,13, 309 2 o 2 pa hways, h ee o EB-O ho + O 2 and six o EB-O ho + NO 2 . I was ound ha , a a mosphe ic condi ions, he majo p oduc o he o me eac ion is e hyl-phenol while o he la e eac ion one ob ains ni o-e hylbenzene as he majo p oduc . The calcula ed a e cons an s show an in e es ing pa allelism and ag eemen wi h he expe imen al a e cons an s o he oluene-OH adduc eac ions wi h O 2 and NO 2 . Since e hylbenzene is expec ed o be a p ecu so o seconda y o ganic ae osols, he p esen heo e ical s udy migh p o ide a use ul heo e ical basis o in e p e ing he oxygen-con aining and ni ogen- con aining o ganics in an h opogenic seconda y o ganic ae osol pa icles. In he ou h pape , Vijayakuma e al. [ 4 ] di e in o he well known and impo an subjec o s a osphe ic ozone chemis y and pe o m a heo e ical s udy on he kine ics o he eac ions o ozone wi h halogen a oms in he s a osphe e. Al hough he impo ance o halogens as ca alys s in he des uc ion o ozone is well ecognized, he numbe o heo e ical s udies on he kine ics o O 3 wi h halogens is ela i ely low. In his pape , he au ho s ocused in he imp o emen he heo e ical unde s anding o hese eac ions and ex end he empe a u e ange beyond wha is expe imen ally a ailable, om 180 o 400 K o all h ee halogens wi h a p ima y ocus on a mosphe ically ele an condi ions. Fo he h ee eac ions, he calcula ed a e coe iecien s we e ound o be in good ag eemen wi h he ecommended alues om NASA/JPL and IUPAC, he eby helping unde pin he heo e ical ounda ion o hese impo an ozone-loss eac ions. In he i h and las esea ch pape , Bai [ 5 ] de eloped wo empi ical models o ozone concen a ion o conside ing he indi idual oles o isop ene o mono e penes in a sub- opical Pinus plan a ion in China. P edic ing and unde s anding wha a ec s ozone concen a ion is o c ucial impo ance, since ozone is one o he impo an g eenhouse gases in luencing clima e change on global scale, and a key cons i uen o pollu an s p oduced h ough chemical and pho ochemical eac ions in he a mosphe e. The es ima ed ozone concen a ion was ound o be in ag eemen wi h he ield obse a ions, wi h easonable alida ion esul s. I is sugges ed o con ol human-induced high biogenic ola ile o ganic compounds emissions, egula e plan cu ing, and educe NOx and SO 2 emissions mo e s ic ly han e e be o e, so as o educe O3and ine pa icle o ma ion. Las ly, Tuck [ 6 ] w i es a e iew whe e he p esen s his p oposal o a challenging p og amme o esea ch in heo e ical chemis y in ol ing ab ini io simula ion by molecula dynamics o an ai olume, in o de o quan i a i ely ame he e ec s o u bulence in he a mosphe e. Tuck discusses ha heo e ical chemis y should ha e he abili y o achie e his pu pose, by showing ha u bulence is an eme gen p ope y o luid mechanics a ising om symme y b eaking, d i en by he Gibbs ee ene gy o he mos ene ge ic molecules ac ing o minimize ene gy densi y. Tu bulence a ec s chemis y, adia ion and luid dynamics a a undamen al, molecula le el and is hus o basic conce n o heo e ical chemis y as i applies o he a mosphe e, which consis s o molecules in mo ion. Funding: This esea ch ecei ed no ex e nal unding. Acknowledgmen s: The edi o s would like o hank he au ho s o hei con ibu ions, he e iewe s o hei cons uc i e and aluable commen s o imp o e he manusc ip s, and he edi o ial o ice o he suppo in publishing his issue. Con lic s o In e es : The au ho decla es no con lic o in e es . Re e ences 1. Ga ido, J.D.D.; Balles e , M.Y. A Theo e ical S udy o he N2 + H2 Reac i e Collisions o High Vib a ional and T ansla ional Ene gies. A mosphe e 2021,12, 1349. [C ossRe ] 2. Xie, H.-B.; Elm, J. T i-Base Syne gy in Sul u ic Acid-Base Clus e s. A mosphe e 2021,12, 1260. [C ossRe ] 3. Lu, T.; Huang, M.; Lin, X.; Zhang, W.; Zhao, W.; Hu, C.; Gu, X.; Zhang, W. Theo e ical S udies on he Reac ion Mechanism and Kine ics o E hylbenzene-OH Adduc wi h O2and NO2.A mosphe e 2021,12, 1118. [C ossRe ] 4. Vijayakuma , S.; Ranasinghe, D.S.; Wilmou h, D.M. Kine ics o he Reac ions o Ozone wi h Halogen A oms in he S a osphe e. A mosphe e 2021,12, 1053. [C ossRe ] 5. Bai, J. O 3 Concen a ion and I s Rela ion wi h BVOC Emissions in a Sub opical Plan a ion. A mosphe e 2021 ,12, 711. [C ossRe ] 6. Tuck, A.F. Theo e ical Chemis y and he Calcula ion o he A mosphe ic S a e. A mosphe e 2021,12, 727. [C ossRe ]