Abstract

Anharmonicity in the crystal potential leads to phonon interactions which result in vibrational relaxation and dephasing. For many crystal systems a satisfactory description of vibrational relaxation is obtained by considering the first anharmonic correction to the crystal potential, namely a cubic interaction. However, recent results on vibrationally sparse systems have shown that the next higher order anharmonic relaxation term (i.e quartic) is necessary to account for the observed thermally induced dephasing [1-3]. In this work we focus on the importance of anharmonic relaxation mechanisms by creating a large vibrational energy gap. One expects the mode immediately above the gap to have an increased lifetime relative to other vibrational modes of the molecule due to the absence of any cubic decay channels.

© 1990 Optical Society of America