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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
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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 ]