ISSN:
1089-7690
Quelle:
AIP Digital Archive
Thema:
Physik
,
Chemie und Pharmazie
Notizen:
CBr4 is an archetypal example of a pseudospherical molecule that can form an orientationally disordered phase (phase I, 320 K〈T〈365 K). At lower temperatures, phase II is the stable phase; although it must be more ordered than phase I, different techniques give conflicting results concerning order in phase II. In order to investigate dynamical disorder in phase II, the heat capacity of CBr4 has been measured in the temperature range 30–305 K. No phase transitions were found in this region. The calculated heat capacity, with contributions due to low-frequency translation and rotational-vibrations of the rigid CBr4 molecules, as well as internal motions, fits the experimentally derived Cv data to within 3%. Virtually full excitation of rigid molecule rotation-vibrations at very low temperatures (∼45 K) is consistent with the observation of a low-temperature elevation in the calculated Grüneisen parameter. © 1995 American Institute of Physics.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.470444
Permalink