The approach-induced I-2(E0(g)(+) (M)over-right-arrow D0(u)(+)) transitions, M = He, Ar, I-2, N-2, CF4

Citation
Me. Akopyan et al., The approach-induced I-2(E0(g)(+) (M)over-right-arrow D0(u)(+)) transitions, M = He, Ar, I-2, N-2, CF4, CHEM PHYS, 263(2-3), 2001, pp. 459-470
Citations number
33
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
CHEMICAL PHYSICS
ISSN journal
03010104 → ACNP
Volume
263
Issue
2-3
Year of publication
2001
Pages
459 - 470
Database
ISI
SICI code
0301-0104(20010115)263:2-3<459:TAI(DT>2.0.ZU;2-R
Abstract
The dependencies of rate constant of the intramolecular I-2(EOg+->(M) D0(u) (+)) approach-induced transition, M = He, Ar, I-2, N-2, CF4, On the vibrati onal nu (E) nu (D), rotational J(E) J(D) numbers. energy gaps, and Franck-C ondon factors of the combined levels have been studied at nearly single-col lision conditions by the OODR method. It has been shown that the observed a pproach-induced intramolecular transitions (AIIT) are nonresonant, correspo nd to loss of 100-700 cm(-1) or gain of 160 cm(-1) energy. For M not equal CF4 their cross-sections are independent of initial J(E) approximate to 50- 110 number and up to 60 (M = He) times less than maximum cross-section of t he extremely long-range nearly resonant I2(E,nuE <-> D-I2(X),nu (D) AIIT [C hem. Phys. 242 (1999) 263]. The nonresonant transition corresponding to los s of up to 160 cm(-1) energy was found out for M = I-2, as well, but its cr oss-section is approximately nine times less than the maximum cross-section of the nearly resonant I-2(E.nu (E)<->D-I2(X).nu (D)) processes. The u <-> g and Delta Omega = 0 propensity rules are valid in the I-2(E) + M -> I-2 (ion-pair states)/ M AIIT. The vibrational and rotational distributions of the D state levels depend on the M nature. The J(E) dependence of the AIIT rate constant in the M = CF4 case has been found out. For J(E) = 110 rate c onstant is close to that of resonance approach-induced one, and the single rovibronic nu (D), J(D) approximate to 110 level corresponding to loss of a bout 1290 cm(-1) energy is populated. It has been shown that the data obser ved in this work and Chem. Phys. 242 (1999) 263 can be qualitatively explai ned in the framework of model of collision (approach) with large impact par ameter. (C) 2001 Elsevier Science B.V. All rights reserved.