Ultrasonic Velocity and Attenuation in Alkali Halides Containing CN⁻ II. Theoretical Interpretation

Abstract

The experimental results presented in Part I are interprvted in terms of the continuum elastic dipole theory, assuming that asymmetric lattice ml?xation perpendicular to the CN-axis results in a dipole tensor with three different principal axes, one of which is the CN-axis. The equilibrium positions are [OOl], [llo], and [llO] and their equivalents. Acoustic interaction with hindered rotor states was also observed.

Kerr effect and birefringence from paraelectric CN− defects in nine alkali halides

“…A recent investigation, probing the orientation CN-states in KC1 under various stresssplitting by resonance absorption of tuneable monochromatic phonons [ 121 came to the same conclusion on the defect symmetry. These three recent works [lo to 121 together with the older ultrasonic study [2], which all agree on the measured size and symmetry of the elastic dipole, establish conclusively the (111) symmetry of the CNelastic dipole in KC1, KBr, K I , and RbC1.…”

Microdynamics of the Internal Friction in Solids

“…I n case of the [110] stress, for instance, we find (14) The details of the relaxat,ion processes of the Lit-ceiitcr are still not well understood. From the measurements of the ultrasonic attenuation an estimate of the relaxation time zR has been obtained [22]. zB is of the order 10-l' -10-l0 s.…”