Mode-specific intermolecular vibrational energy transfer. II. Deuterated water and potassium selenocyanate mixture

Vibrational energy transfer from the first excited state (2635 cm(-1)) of the O-D stretch of deuterated water (D2O) to the 0-1 transition (2075 cm(-1)) of the CN stretch of potassium selenocyanate (KSeCN) in their 2.5:1 liquid mixture was observed with a multiple-mode two dimensional infrared spectroscopic technique. Despite the big energy mismatch (560 cm(-1)) between the two modes, the transfer is still very efficient with a time constant of 20 ps. The efficient energy transfer is probably because of the large excitation coupling between the two modes. The coupling is experimentally determined to be 176 cm(-1). An approximate analytical equation derived from the Landau-Teller formula is applied to calculate the energy transfer rate with all parameters experimentally determined. The calculation results are qualitatively consistent with the experimental data. (C) 2010 American Institute of Physics. [doi:10.1063/1.3458825]