ANHARMONICITY AND LIFETIME OF THE CH STRETCH MODE ON DIAMOND H C(111)-(1X1)/

The anharmonicity and lifetime of the CH stretching vibration of the H -terminated diamond H/C(111)-(1 x 1) surface are investigated. It is f ound that the nu1 --> 2 transition is 110 cm-1 lower than the nu0 --> 1 fundamental. Theoretical calculations show good agreement with the e xperimental observations and predict the existence of a strongly bound two-phonon bound state. A vibrational lifetime of 19 ps and a similar ground-state recovery time are measured.