Lattice Dynamics and Specific-Heat Data for Rocksalt-Structure Alkali Halides

Abstract

Vibrational distribution functions are derived for a number of rocksalt-structure alkali halides using a more refined treatment of the interionic forces than that provided by regarding them as rigid point charges.The dipole moment at any given ion site is calculated taking into account the contribution from the deformation of the electron distribution resulting from both polarization and overlap repulsion between nearest neighbors. In this way the dipole-dipole part of the Coulomb interaction is treated self-consistently.Both room temperature and 0°K input parameters are used, and the derived specific-heat data are compared with experimental results. The over-all agreement with experiment is significantly better than that obtained by treating the ions as rigid point charges.Sets of phonon dispersion curves are also given. For NaI they are in much better agreement with those determined experimentally by inelastic neutron scattering than are the rigid ion curves. There appears to be close agreement with the results of the "shell-model" calculations.

Thermal neutron scattering data for 7LiF and BeF2

“…The computed lattice parameters of BeF 2 and 7 LiF are in well agreement with experimentally reported [20][21][22]. The lattice constants values for BeF2 are a = 4.85Å, and c = 5.335Å.…”

Photocurrent in Ytterbium-Activated Alkali Halides

“…The resultant value of Q is in agreement with that reported in [16,17] where both theoretical and experimental temperature dependencies Q(T) are represented. The experimental values were determined from the temperature dependencies C V (T) to be Q 205 K [16] and Q 212 K [17] for KCl at 250 K, with further increase in temperature, they tend to decrease.…”

“…The experimental values were determined from the temperature dependencies C V (T) to be Q 205 K [16] and Q 212 K [17] for KCl at 250 K, with further increase in temperature, they tend to decrease.…”

Nitrogen-vacancy centres in diamond: internal dynamics and nanoscale measurements

“…In bulk diamond, T D is around 2220 K. We set T D as a fitting parameter in our calibration, however, and find that in nanodiamond T D is (1614 ± 23) K. This is expected, as it is a well-established fact that the Debye temperature can vary in similar materials [193]. The Debye temperature can also vary significantly when far away from the low-temperature regime in which the 2220 K value was measured [194].…”