Jc. Deak et al., WHEN VIBRATIONS INTERACT - ULTRAFAST ENERGY RELAXATION OF VIBRATIONALPAIRS IN POLYATOMIC LIQUIDS, Chemical physics letters, 293(5-6), 1998, pp. 405-411
The ultrafast IR-Raman technique is used to compare picosecond timesca
le vibrational energy relaxation (VR) of a polyatomic liquid, acetonit
rile (CH3CN), following excitation of either a C-H stretching fundamen
tal (similar to 3000 cm(-1)) or a pair of vibrations at about the same
energy, the C=N stretch and C-C stretch. When the vibrational pair is
excited via combination band pumping, the C=N stretch lifetime decrea
ses by more than an order of magnitude, and an oscillation is observed
in the C-C stretch population. These studies of a pair of interacting
vibrations on the same molecule provide insight into the complex beha
vior expected from vibrationally excited nascent products of chemical
reactions of condensed-phase polyatomic molecules. (C) 1998 Elsevier S
cience B.V. All rights reserved.