PICOSECOND IR HOLE-BURNING SPECTROSCOPY ON HDO ICE IH

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 $26{\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ are measured, proving the OH band to be inhomogeneously broadened. The inhomogeneous distribution having a half width of approximately $25{\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ can be related to structural disorder in ice. A vibrational lifetime of $0.5\mathrm{ps}l~{T}_{1}l~2\mathrm{ps}$ 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.