Energy relaxation and reorientation of the OH mode of simple alcohol molecules in different solvents monitored by transient IR spectroscopy

Two-color pump-probe spectroscopy is performed within the OH stretching reg ion of monomeric methanol, l-decanol, and 2,2-dimethyl-3-ethyl-3-pentanol d issolved in different solvents CnClm. From the isotropic component of the p robe transmission signal we deduce the lifetime of the OH stretching vibrat ion to vary between 8 and 10 ps. The molecular reorientation is directly ob served from the anisotropic signal to occur in the range of 2 up to 7 ps. A dditional information is presented, giving evidence for an inhomogeneous br oadening of the monomeric OH vibration and finite phase relaxation of the o rder of 1 ps. (C) 1999 Elsevier Science B.V. All rights reserved.