Modehyphen;tohyphen;mode energy transfer in collisions betweenS1state aniline and Ar, CO, CO2, C2H2, C3H4, OCS, Xe, and N2O

摘要

SVL fluorescence spectroscopy was used to study Vhyphen;T,R processes in collisions of 00aniline with Ar, Xe, CO, CO2, OCS, N2O, acetylene, and allene. Populations were monitored in eight aniline vibronic levels. To first order, the experimental propensity rules for singlehyphen;collision up pumping of 00aniline to these levels are identical for all collision gases. An exception is the unusually large rate constant for population of the 11level in collisions with allene, whose 111level is nearly degenerate with theI1level in aniline; this may be evidence of an important Vndash;V process. The endoergic uphyphen;pumping probabilities correlate well with mgr;1/2for rare gas partners, but poorly for the other collision gases. No evidence is found that Vhyphen;R processes contribute substantially to the rate constants for aniline in collision with CO or the polyatomic gases. The quantitative propensity rules provide a basis for a modehyphen;tohyphen;mode collisional energy transfer theory, developed by Freed, in which the observed large Vhyphen;T,R cross sections arise as a direct consequence of the intramolecular intermode coupling within large molecules such as aniline.