The elastic constants and related properties of β-HMX determined by Brillouin scattering

Authors

Lewis L. Stevens, University of Nebraska-LincolnFollow
Craig J. Eckhardt, University of Nebraska - LincolnFollow

Date of this Version

4-1-2005

Comments

Published by American Institute of Physics. J. Chem. Physics 122, 174701 (2005). ©2005 American Institute of Physics. Permission to use. http://jcp.aip.org/.

Abstract

By scattering from a variety of acoustic phonons, a complete stiffness tensor has been determined for crystalline β-HMX. The results are compared with recent experimental and theoretical determinations of the elastic constants and bulk modulus. Reasons for disagreement are discussed in terms of experimental limitations and anharmonic effects. The observed ordering of stiffness constants, C₁₁ (18.4 GPa), C₂₂ (14.4 GPa), and C₃₃ (12.4 GPa), is qualitatively associated with physical phenomena including cleavage planes, patterns in crystal growth, and molecular packing. This interpretation is further corroborated by the linear compressibilities plotted in three crystallographic planes. The Voigt–Reuss–Hill bulk and shear moduli were found to be 9.9 and 3.7 GPa, respectively. The elasticity of b-HMX is also discussed in relation to proposed mechanisms for the initiation of detonation.