Picosecond vibrational spectroscopy of intermolecular energy transfer and overtone relaxation in liquid bromoform

Intermolecular energy transfer in liquid bromoform and d-bromoform was investigated by help of picosecond IR and Raman spectroscopy. For a comprehensive interpretation of the corresponding results the study of C-H bending overtone (2 nu(4)) relaxation was necessary; the effective vibrational lifetime of this vibrational mode was determined to T-1 = 3 +/- 1 ps. For the intermolecular transfer a dominating process between the intramolecularly equilibrated C-Br stretching modes nu(2) and nu(5) of CHBr3 and CDBr3 with a rate constant of 4.10(10) s(-1) was recognized. Other possible channels, particularly the one between the quasi resonant modes nu(1)(C-D) and 2 nu(4)(C-H) were found to be negligible.