Thermophysical Properties of Process Gases

Published

November 1, 1999

Author(s)

John J. Hurly, Michael R. Moldover

Abstract

We measured the speed of sound in the process gases Cl₂, HBr, BCl₃, and in the surrogate gases SF₆, CF₄, and C₂F₆. The data range up to 475 K (200 C) and from 25 kPa to 1500 kPa (or to 80% of the vapor pressure for condensable gases). The data were analyzed to obtain ideal-gas heat capacities C_p⁰(T) with uncertainties of 0.001 C_p⁰. The data were also used to parametrize model pair and three-body intermolecular potentials which were used to estimate the properties of the gases up 800 K, temperatures well above the range of the data. From the model potentials, we deduced the equation of state P(V,T) and the viscosity Η(T). For gases where other data exist, we find the errors in the estimates are less than 0.001 V and 0.1 Η (The thermal conductivity κ(T), can be estimated from Η(T) with an uncertainty of 10%.) Plans include measuring the speed of sound in WF₆, direct acoustic measurements of the transport properties, and dissemination of the results as a user-friendly data base for PCs and in publications in archival journals.

Proceedings Title

Proceedings of SEMICON West '99, Workshop on Gas Distribution Systems

Conference Dates

July 11-12, 1999

Conference Title

SEMICON

Pub Type

Conferences

Keywords

equation of state, intermolecular potential, semiconductor gases, sound speed, thermoconductivity, thermodynamic properties, transport properties, viscosity

Citation

Hurly, J. and Moldover, M. (1999), Thermophysical Properties of Process Gases, Proceedings of SEMICON West '99, Workshop on Gas Distribution Systems (Accessed April 25, 2024)