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Measurement of the specific refractivities of CF4 and C2F6In order to relate the measured fringe shift of an interferometer to the density of a medium, the relation between density and refractive index, which is expressed by the specific refractivity, must be known. In the present paper, the specific refractivities of the wind tunnel test gases CF4 and C2F6 are determined in order to verify estimations based on the atomic refractivities of carbon and fluorine. A Twyman-Green two-beam interferometer with a 633-nm He-Ne laser light source was used to measure the specific refractivity as a function of fringe shift as the density of the gas was changed. Values of 0.122 and 0.131 cu cm/g were obtained for CF4 and C2F6 respectively at a temperature of 300 K, which are within 1% of the values computed from the atomic refractivities.
Document ID
19800061169
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Burner, A. W.
(NASA Langley Research Center Hampton, VA, United States)
Goad, W. K.
(NASA Langley Research Center Hampton, Va., United States)
Date Acquired
August 10, 2013
Publication Date
July 15, 1980
Publication Information
Publication: Journal of Chemical Physics
Volume: 73
Subject Category
Instrumentation And Photography
Accession Number
80A45339
Distribution Limits
Public
Copyright
Other

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