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Inelastic molecular collisions with an orientation‐averaged interaction energy
Author(s) -
Shin Hyung Kyu
Publication year - 1968
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560020207
Subject(s) - diatomic molecule , atomic physics , chemistry , molecule , orientation (vector space) , potential energy , molecular vibration , vibrational energy , function (biology) , energy (signal processing) , molecular physics , physics , excited state , quantum mechanics , geometry , mathematics , organic chemistry , evolutionary biology , biology
The importance of molecular orientations for vibrational‐translational energy transfers between diatomic molecules has been investigated. An angle‐dependent potential function is assumed, and it is averaged over the orientations and vibrations of colliding molecules. For I 2 I 2 and Cl 2 Cl 2 , it is found that the calculated average vibrational transition probability for a colinear collision is over‐estimated by large factors (1/γ) compared to that obtained when all possible molecular orientations are considered. At 300 0 K, 1/γ = 34.4 for I 2 I 2 and 17.6 for Cl 2 Cl 2 , while it is 6.8 and 5.9 for N 2 N 2 and O 2 2 , respectively. It is also shown that 1/γ decreases rapidly as temperature increases. At 2000 0 K, 1/γ ≈ 3 for I 2 I 2 , Cl 2 Cl 2 , and N 2 N 2 , while it is ≈ 2.5 for O 2 O 2 . In general, when the molecules are large, and when strong attractive forces act between them, 1/γ is very large at low temperatures (<1000 0 K).