THERMODYNAMIC PROPERTIES OF CH$sub 4$ AND CD$sub 4$. INTERPRETATION OF THE PROPERTIES OF THE SOLIDS

Journal Article · Thu Aug 01 04:00:00 EDT 1963 · Journal of Chemical Physics (U.S.)

DOI:https://doi.org/10.1063/1.1734303· OSTI ID:4658114

Colwell, J H; Gill, E K; Morrison, J A

The results of calorimetric measurements of the heat capacities of solid and liquid CH/sub 4/and CD/sub 4/, the heats of fusion of both substances and the heat of vaporization of CD/sub 4/ are given. The results for the solids, which extend from 2.3 deg K to the triple points, were analyzed in some detail. In order to account for the apparent zero-point entropies of both CH/sub 4/ and CD/ sub 4/ quantitutively, it was necessary to recognize the existence of different nuclear spin species (as with ortho and para hydrogen) and to say that, as T approaches 0 deg K, each species tends to occupy its lowest available molecular energy level. No conversion between the different species was observed. The relevance of these findings to the usual applications of the third law of thermodynamics is discussed. The thermal transitions which occur in solid CH/sub 6/and CD/sub 4/ (as well as in the partially deuterated methanes) were also examined and an attempt was made to correlate the thermodynamic results with information derived from other experiments (e.g., spectroscopic, neutron scattering) and from theory. While correlations are possible, the fundamental causes of the transitions can still not be established. (auth)

• Research Organization: National Research Council, Ottawa
• Sponsoring Organization: USDOE
• NSA Number: NSA-17-033910
• OSTI ID: 4658114
• Journal Information: Journal of Chemical Physics (U.S.), Journal Name: Journal of Chemical Physics (U.S.) Vol. Vol: 39; ISSN JCPSA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ATOMIC MODELS
CALORIMETERS
CHEMISTRY
CONFIGURATION
DEUTERIUM COMPOUNDS
DIAGRAMS
ENERGY
ENTROPY
EVAPORATION
HYDROGEN
HYDROGEN- PARA
HYDROGEN-ORTHO
ISOMERS
ISOTOPE EFFECTS
ISOTOPES
LIQUIDS
LOW TEMPERATURE
MATHEMATICS
MEASURED VALUES
MELTING
METHANE
MOLECULES
NEUTRON BEAMS
NUCLEAR THEORY
PHASE DIAGRAMS
SCATTERING
SOLIDS
SPECIFIC HEAT
SPECTROSCOPY
SPIN
STABILITY
TEMPERATURE
THERMODYNAMICS
VARIATIONS