Mode-specific intermolecular vibrational energy transfer. I. Phenyl selenocyanate and deuterated chloroform mixture

Abstract

Vibrational energy transfer from the first excited state (2252 cm−1) of the C–D stretch of deuterated chloroform (DCCl3) to the 0-1 transition (2155 cm−1) of the CN stretch of phenyl selenocyanate (C6H5SeCN) in their 1:1 liquid mixture was observed with a pump/probe two-color two dimensional infrared spectroscopic technique. The mode-specific energy transfer can occur mainly because of the long vibrational lifetime of the CN stretch first excited state (∼300 ps) and the relatively strong hydrogen-bond between the C–D and CN (calculated H-bond formation energy in gas phase ∼−5.4 kcal/mol). The mode-specific energy transfer is relatively low efficient (only ∼2%), which is mainly because of the relatively short vibrational lifetime (∼9 ps) of the C–D stretch first excited state and the big donor/acceptor energy mismatch (97 cm−1) and the slow transfer kinetics (1/kCD→CN=330 ps).