Transient hole-burning experiments using picosecond ir pulses in the region of the OH stretching vibration of crystalline HDO (in ${\mathrm{D}}_2\mathrm{O}$) ice are reported; holes with a minimum width of $26{\mathrm{cm}}^{\mathrm{-}1}$ are measured, proving the OH band to be inhomogeneously broadened. The inhomogeneous distribution having a half width of approximately $25{\mathrm{cm}}^{\mathrm{-}1}$ can be related to structural disorder in ice. A vibrational lifetime of $0.5\mathrm{ps}<~T_1<~2\mathrm{ps}$ is found for the OH stretching mode. Additional features in the transient data are attributed to the dissipation of excess energy; particularly microscopic energy flow in the immediate surroundings of primarily excited OH groups can be monitored.

• Received 13 June 1997

DOI:https://doi.org/10.1103/PhysRevB.56.R14231