Vibrational energy migration in a hydrogen-bonded dimer probed with ultrafast time-resolved spectroscopy

We demonstrate transient spectroscopy within the OH-stretching region of 2,2-dimethyl-3-ethyl-3-pentanol diluted in CCl4, which associates to hydrogen-bonded dimers only. Strong evidence for migration of vibrational excitation from the proton acceptor to the donor and vice versa is deduced from the data with a time constant <1 ps. Reorientation of the OH-group of the proton donors and acceptors proceeds notably slower with time constants of 8 and 4 ps, respectively, indicating the minor contribution of structural relaxation to the measured fast dynamics.