R. Laenen et al., IR spectroscopy of hydrogen-bonded methanol: Vibrational and structural relaxation on the femtosecond time scale, J PHYS CH A, 103(50), 1999, pp. 10708-10712
Two-color pump-probe spectroscopy is performed with femtosecond time resolu
tion in the OH-stretching region of methanol oligomers in a CCl4 mixture at
room temperature. The measured isotropic component of the probe transmissi
on signal gives direct access to the lifetime of the OH-stretching vibratio
n. 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 br
eaking of the excited oligomers is noticed. Recombination proceeds with a t
ime constant of 9 ps, Comparison to earlier work on water and related alcoh
ols is also made.