Hot luminescence of self-trapped excitons in Xe crystal under X-ray and two-photon laser excitation

Abstract

A nonperturbative theory of anharmonic multiphonon decay of strong local vibration in crystal is developed, which predicts sharp acceleration of the process caused by cubic anharmonicity near characteristic amplitudes (typically A∼0.3 Å), and abrupt switching-off of the processes caused by higher order anharmonicities at larger amplitudes (typically A∼1 Å). The first experimental observation of such a process is reported: strong acceleration of two-phonon decay of Xe2∗ quasi-molecules is found in solid xenon. The experiment is based on X-ray and two-photon laser excitation (using an excimer laser emitting at 193 and 248 nm) of hot luminescence of Xe2∗.