Heyne, K; Nibbering, ETJ; Elsaesser, T; Petkovic, M; Kühn, O
JOURNAL OF PHYSICAL CHEMISTRY A 2004, 108(29), p. 6083-6086
Femtosecond two-color pump-probe experiments in the mid-infrared range demonstrate that excitation energy of the hydrogen-bonded O-H stretching oscillator of phthalic acid monomethyl ester is redistributed on a subpicosecond time scale along the O-H bending vibration. The O-H stretching and O-H bending lifetimes are 220 and 800 fs, respectively. Quantum dynamical model calculations of the energy flow induced by O-H stretching excitation reveal a relaxation mechanism involving cascaded energy redistribution along the O-H bending vibration and two O-H out-of-plane deformation modes at similar to700 and 800 cm-1.