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

Vibrational energy transfer from the first excited state (2252 cm(-1)) of the C-D stretch of deuterated chloroform (DCCl(3)) to the 0-1 transition (2155 cm(-1)) of the CN stretch of phenyl selenocyanate (C(6)H(5)SeCN) 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 (similar to 300 ps) and the relatively strong hydrogen-bond between the C-D and CN (calculated H-bond formation energy in gas phase similar to-5.4 kcal/mol). The mode-specific energy transfer is relatively low efficient (only similar to 2%), which is mainly because of the relatively short vibrational lifetime (similar to 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/k(CD -> CN)=330 ps). (C) 2010 American Institute of Physics. [doi: 10.1063/1.3429170]