PHONON WIDTHS IN NACL, KCL, AND RBCL FROM NEUTRON MEASUREMENTS

In a systematic study of phonon dispersion relations in NaCl, KCl, and RbCl results were also obtained on phonon widths in some branches, primarily at 80 °K, but to some extent also at 300 °K. The widths for all three chlorides are found to be mostly between 0.04 and 0.10 (in units of 1013 rad s−1). In all cases the increase of the width between 80 and 300 °K is less than the estimated error of the width at 80 °K. The results are discussed and some of the difficulties of such measurements are pointed out. Copyright © 1969 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim