Elastic constants of neon single crystals determined by Brillouin scattering

Abstract

High-resolution Brillouin spectroscopy has been used to determine the adiabatic elastic constants of solid neon at 24.3 K. Single crystals were grown for this investigation, and laser-excited spectra were recorded for various crystal orientations. The observed spectra included the longitudinal Brillouin doublet and, usually, the low-frequency transverse doublet. Their frequency shifts for eight different single crystals were used to obtain the following values for the adiabatic elastic constants (in kbar): $C_{11}=11.70\mathrm{}\pm 0.21$, $C_{12}=7.31\mathrm{}\pm 0.17$, and $C_{44}=6.02\mathrm{}\pm 0.15$. From these values, it is found that the elastic anisotropy parameter $A=2.74\mathrm{}\pm 0.10$, and the adiabatic bulk modulus $B_s=8.77\mathrm{}\pm 0.17$ kbar. The best agreement between these experimental values of the elastic constants and theoretical values is obtained for quasiharmonic calculations using a Mie-Lennard-Jones (6-12) all-neighbor potential.