Chemical Physics Letters, Vol.512, No.4-6, 178-183, 2011
Intramolecular vibrational dynamics in bis(trifluoromethyl)keten excited by resonant femtosecond IR radiation
Vibrational dynamics in different modes of (CF3)(2)CCO molecule induced by resonant femtosecond IR excitation of the nu(1) mode is studied. Selective multiphoton excitation of this mode is observed up to the level v = 7. Intramolecular vibrational redistribution (IVR) causes relaxation of the nu(1) mode with a time constant tau(IVR) = 5 ps. The 'instantaneous' (tau << tau(IVR)) transient absorbance Delta OD signal at nonresonant modes nu(2), nu(3), and nu(4) is revealed. Subsequent evolution of the Delta OD signal and the corresponding time constants are different for different modes, which we associate with different migration pathways of the vibrational energy. (C) 2011 Published by Elsevier B.V.