Table of Contents
Laser Chemistry
Volume 14, Issue 4, Pages 191-200

Vibrational Relaxation of the 2ν5 Overtone of CDCl3 Following Tea CO2 Laser Excitation of the ν4 Mode

1Student of Licenciatura en Ciencias Físicas., Fac. Cs. Ex. y Nat., Universidad de Buenos Aires, Argentina
2Research career of CONICET, Argentina
3Laboratoire de Physique Moleculaire et Applications. CNRS., Université Pierre et Marie Curie, Paris, France
4INFIQC, Departamento de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Sucursal 16, C.C. 61, Córdoba 5016, Argentina
5Zufriategui 4380, (1603), Villa Martelli, Bs. As., Argentina

Received 1 May 1993

Copyright © 1994 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The time variation of the 2ν5 fluorescence intensity was measured in CDCl3 excited in the ν4 C–D bending mode by a TEA CO2 laser operating on the 10P(48) line. A fast rise of the fluorescence, with a time constant ≤ 1 μs Torr, was first observed, showing that a fast equilibration of population occurs between the ν4 and ν5 modes through a ν4 ↔ ν5 Coriolis-assisted intermode transfer and a ν5 ↔ 2ν5 near-resonant ladder-climbing process. Then a first fast fluorescence decay was observed and attributed to a (ν4, ν5) → ν2 intermode transfer with a rate constant of (7.10 ± 1.13)ms-1 Torr-1. At last, a much slower decay, with a rate constant of 0.111 ± 0.015 ms-1 Torr-1, results from the less efficient intermode transfer and V–T,R deexcitation processes involving the ν3 and ν6 states, and which compete to relax the gas to a thermodynamic equilibrium.