title: Anomalous temperature dependence of the vibrational lifetime of the OD stretch vibration in ice and liquid water.
abstract: The temperature dependence of the vibrational T1 lifetime of the OD stretch vibration of HDO in H2O ice was measured with femtosecond mid-IR pump-probe spectroscopy. We found an increase of T1 from 480 ± 40 fs at 25 K to 860 ± 60 fs at 265 K. These lifetimes are remarkably shorter than the vibrational lifetime of the OD stretch vibration of HDO in H2O in the liquid phase, which has a value of 1.7 ± 0.1 ps at 274 K and increases to 2.24 ± 0.09 at 343 K. The observed temperature dependence of T1 can be well explained from a relaxation mechanism in which the OD vibration relaxes via energy transfer to the bend-libration combination tones of H2O and HDO.
authors.affiliation: FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands.
authors.forename: W J
authors.initials: WJ
authors.lastname: Smit
authors.forename: H J
authors.initials: HJ
authors.lastname: Bakker