Transient hole burning in the infrared in an ethanol solution

Transient hole burning in the oligomer region of the OH-stretching mode of ethanol dissolved in carbon tetrachloride is demonstrated, using two-color IR spectroscopy with excitation and probing pulses of 2 and 1 ps, respectively. The observed inhomogeneous broadening of the oligomer band is explained via local disorder of the hydrogen bonds. The lifetime of the spectral holes is estimated to be approximately 1 ps, providing evidence for rapid spectral relaxation and/or migration of vibrational excitation. The observed time evolution of excited state absorption from v = 1 to v = 2 levels yields the v = 1 population lifetime of 1.4 ± 0.3 ps. Breaking of the ethanol rings or chains as indicated by longer-lived induced absorption in the dimer/trimer region around 3450 cm^-1 and further spectral features are reported.