Journal of Physical Chemistry A, Vol.103, No.50, 10708-10712, 1999
IR spectroscopy of hydrogen-bonded methanol: Vibrational and structural relaxation on the femtosecond time scale
Two-color pump-probe spectroscopy is performed with femtosecond time resolution in the OH-stretching region of methanol oligomers in a CCl4 mixture at room temperature. The measured isotropic component of the probe transmission signal gives direct access to the lifetime of the OH-stretching vibration. It varies between 0.45 and 0.6 ps, increasing with excitation frequency from 3280 to 3400 cm(-1). After vibrational excitation of the OH-mode, fast spectral relaxation and/or vibrational energy migration with subsequent breaking of the excited oligomers is noticed. Recombination proceeds with a time constant of 9 ps, Comparison to earlier work on water and related alcohols is also made.
Keywords:RESOLVED INFRARED-SPECTROSCOPY;HOLE-BURNING SPECTROSCOPY;TEMPERATURE-DEPENDENCE;ENERGY RELAXATION;PULSES;GENERATION;DYNAMICS;ETHANOL;LIFETIME;LIQUIDS