Atomic Energy of Canada Limited

About: Atomic Energy of Canada Limited is a company organization based out in Ottawa, Ontario, Canada. It is known for research contribution in the topics: Zirconium alloy & Neutron. The organization has 4845 authors who have published 4826 publications receiving 102951 citations.

LATTICE DYNAMICS OF ALKALI HALIDE CRYSTALS. II. EXPERIMENTAL STUDIES OF KBr AND NaI

Abstract: Dispersion curves for the lattice vibrations propagating in the [$00\ensuremath{\zeta}$], [$\ensuremath{\zeta}\ensuremath{\zeta}0$], and [$\ensuremath{\zeta}\ensuremath{\zeta}\ensuremath{\zeta}$] directions in NaI at 100\ifmmode^\circ\else\textdegree\fi{}K and in KBr at 90\ifmmode^\circ\else\textdegree\fi{}K have been measured using neutron spectrometry, and the results compared with calculations based on a simple shell model. Both substances obey the Lyddane-Sachs-Teller relation. In addition, some measurements were made on KBr at 400\ifmmode^\circ\else\textdegree\fi{}K; most frequencies showed a decrease of a few percent. At this temperature, the acoustical modes show no significant energy broadening, the transverse optical modes show slight broadening, and the longitudinal optical modes show very considerable broadening. The anomalous broadening of the LO modes is not yet understood and requires further study. It appears to be specimen-dependent as well as temperature-dependent.

A unified structural approach to linear carbon polytypes

Abstract: Compounds obtained by high-temperature treatment of graphite are thought to be linear carbon polytypes with sp-configuration and carbon–carbon chains, either conjugated triple bonded or cumulated double bonded, parallel to the c-axis. At least 10 crystallographically documented linear carbon forms (carbynes) have been reported. To relate the contradictory and confusing information found in the literature, a simple classification is suggested here based on a linear relationship between number of atoms in a chain (n) and the unit cell parameters a0 and c0 of all carbyne forms known. It is assumed that chains are kinked, and that the distribution of kinked spacings may be a function of the temperature of formation of the carbyne forms in question.