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Molecular relaxation processes in triatomic molecules. II. The N 2 –CO 2 system
Author(s) -
Thommarson Ronald L.,
Berend George C,
Benson Sidney W.
Publication year - 1974
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550060203
Subject(s) - chemistry , atomic physics , triatomic molecule , excited state , quadrupole , atom (system on chip) , relaxation (psychology) , range (aeronautics) , anharmonicity , morse potential , vibration , transfer (computing) , potential energy , molecular physics , molecule , physics , quantum mechanics , psychology , social psychology , materials science , organic chemistry , parallel computing , computer science , composite material , embedded system
Translation–vibration ( T–V ) and vibration–vibration ( V–V ) energy transfer processes in the N 2 –CO 2 system were investigated using classical trajectory techniques. Two empirical interaction potentials were employed. One is comprised of independent, atom–atom Morse‐type functions operating between nonbonded atoms. The other included these atom–atom Morse functions plus Coulombic terms to account for the quadrupole–quadrupole intertion. Both interaction potentials led to similar T–V results. However, the result that CO 2 ( v 3 ) is excited ∼10 3 times more efficiently than N 2 ( v = 1) was obtained, which is at variance with existing analytical theories of T– V energy transfer employing purely repulsive short‐range potentials. Different V–V energy transfer probabilities were obtained from the two interaction potentials. The most important finding is that only when electrostatic orientation effects are combined with short‐range repulsive interactions is the near‐resonant\documentclass{article}\pagestyle{empty}\begin{document}$${\rm N}_{\rm 2} {\rm (}v = {\rm 1)} + {\rm CO}_{\rm 2} {\rm (000)} \to {\rm N}_{\rm 2} {\rm (}v = {\rm 0)} + {\rm CO}_{\rm 2} {\rm (001)}$$\end{document}V–V transfer found to be the dominant energy transfer path. This interaction potential also crudely accounts for the negative temperature dependence observed for this near‐resonant V–V transfer at low temperatures (300–1000°K).