Effect of gravity on density distributions and orthopositronium annihilation rates in ethane and methane near the critical point

Journal Article · Wed Jun 01 04:00:00 EDT 1983 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.444637· OSTI ID:6158280

Sharma, S C; Kafle, S R.S.

The effect of gravity on density distributions has been studied in ethane and methane near their critical points using the linear-model parametric equation of state. The results obtained from this study are used to further understand the sensitivity of orthopositronium annihilation rates to density fluctuations in molecular gases. It is shown that the influence of gravity is too small to account for the recently observed dependence of orthopositronium annihilation rates on the density of ethane gas at 306.4 K. However, a significant variation in local density vs height is calculated at temperatures closer to the gas--liquid critical point. The density and temperature dependencies of the annihilation rates of orthopositronium atoms, recently observed in ethane and methane gases, are discussed in terms of the findings of this study.

• Research Organization: Center for Positron Studies, Department of Physics, The University of Texas at Arlington, Arlington, Texas 76019
• OSTI ID: 6158280
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 78:11; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
ALKANES
ANNIHILATION
BASIC INTERACTIONS
CRITICAL TEMPERATURE
DENSITY
ELECTROMAGNETIC INTERACTIONS
ETHANE
GRAVITATION
HYDROCARBONS
INTERACTIONS
METHANE
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
POSITRONIUM
POSITRONIUM CHEMISTRY
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE