Eleventh International Conference on Internal Friction and Ultrasonic Attenuation in Solids
J. Phys. IV France 06 (1996) C8-531-C8-534
Relaxation of the Off-Centered H- ion at E'4 Defect Center in α-QuartzA. Manov, M. Kirtcheva and L. Mihailov
Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia, Bulgaria
The cluster calculations of the configuration with energy minima for E'4 defect center indicate a double-well potential energy profile for off-centered displacement of the H- ion substituting for the oxygen at the E'4 center in α-quartz. Pseudo Jahn-Teller effect formalism is applied to interpret the cluster calculated data. The Schrödinger equation with pseudo Jahn-Teller potential energy is numerically solved. The eigenvalue spectrum and corresponding wave functions of these lowered symmetry centers are found. Applying a modified reaction rate method the relaxation times of H- ion are computed. The acoustic losses Q-1 are computed and compared to experimental data. The specific profile of the adiabatic potential energy, the calculated energy spectrum and the corresponding relaxation times denote that H- ion is a mixed tunneling-relaxation system. The presented theoretical results may be useful in forecasting the radiation response of α-quartz.
© EDP Sciences 1996