Transient IR hole burning on hydrogen-bonded liquids

Transient hole-burning spectroscopy of associated ethanol molecules in the infrared: Structural dynamics and evidence for energy migration

“…20 The smaller linewidth determined here for the ethanol solution may be explained by more pronounced motional narrowing in the liquid phase. Furthermore this holewidth is comparable to the very recently published value for a significantly higher concentrated ethanol solution in CCl 4 of 2.4 M. 21 The lifetime of the spectral hole of hole ϭ 1.2Ϯ0.2 ps agrees with the number found in previous investigations for a higher concentration of 1.2 M ͑Ref. 13͒; hole may be governed by three processes: population decay to the vibrational ground state, energy migration to neighboring ethanol molecules with shifted frequency positions, and structural relaxation of the excited OH groups also generating frequency shifts.…”

Spectral Hole Burning andEvidence for Vibrational EnergyMigration of H‐Bonded MoleculesObserved With Transient InfraredSpectroscopy

“…Via excitation of a selected ensemble of molecules we observe transient hole burning in the homogeneously broadened OH-band with a holelifetime of 1.2 ps. The spectral hole, which has been also observed in experiments with even higher ethanol concentration of 1.2 M [8] and 2.4M [10], exhibits a width of about 45cmand displays the local disorder of the H-bonds due to varying bond angles and distances. The transient hole vanishes mainly via the proposed migration of vibrational quanta along the chain of associated molecules with a time constant 7-mig < ps, as deduced from the bleaching component shown in Figures b-d and the fact, that reorientation of the molecules is noteable slower.…”

Transient spectral hole burning and hydrogen-bond breaking determined in different solutions of ethanol in deuterated ethanol

“…In this investigation a spectral hole width of Ϸ100 cm Ϫ1 is obtained at room temperature. 21 The difference could be explained, for example, by saturation broadening in the latter experiments as the applied IR pulses exhibit a duration of 4-5 ps, too long to monitor the fast dynamics. In addition, an approximately tenfold higher excitation energy has been applied resulting in a pronounced heating of the sample.…”