Phonon Scattering Times in a Molecular Crystal Below 10K Determined by Optically Detected Acoustic Paramagnetic Resonance

Abstract

A combination of optically detected magnetic and acoustical paramagnetic resonance has been used to determine the phonon scattering time of microwave-frequency phonons in a molecular crystal in the 2- to 7-K temperature range. In contrast to higher-temperature behavior, it is found that the phonon scattering time in the molecular-crystal sample follows the I.andau-Rumer law %e suggest that a good estimate of the phonon scattering time for microwave-frequency phonons in this temperature range is rr = (pv /y v T ) X 10 for any molecular crystal if boundary and inelastic defect scattering can be neglected.