Accession Number : ADA330043

Title :   Absorption of Ultrasound in Organic Crystals.

Corporate Author : ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD

Personal Author(s) : Strenzwilk, Denis F. ; Yedinak, Peter D.

PDF Url : ADA330043

Report Date : APR 1976

Pagination or Media Count : 47

Abstract : In this paper we present our expression for the transition rate for a molecule in an organic crystal to absorb three phonons of lattice energy into the lowest frequency molecular vibrational mode (O+l transition). Our model is a three dimensional simple cubic lattice with nearest neighbor central and noncentral forces between molecules situated at the lattice sites. After making some approximations we compare our expression with the transition rate determined from ultrasonic experiments on benzene, p-dichlorobenzene1 carbon tetrachloride, and cyclohexane and discuss the results, We also point out the improvement Our expression offers over the transition rate derived by Liebermann and used by other investigators.

Descriptors :   *MOLECULAR VIBRATION, *CRYSTALS, *ULTRASONICS, *ORGANIC MATERIALS, FREQUENCY, BENZENE, MOLECULES, RATES, TRANSITIONS, CYCLOHEXANES, PHONONS, ABSORPTION.

Subject Categories : Crystallography
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE