Measured relationship between thermodynamic pressure and refractivity for six candidate gases in laser barometry.

ABSTRACT: Laser refractometers are approaching accuracy levels where gas pressures in the range 1 Pa < p < 1 MPa inferred by measurements of gas refractivity at a known temperature will be competitive with the best existing pressure standards and sensors. Here, the authors develop the relationship between pressure and refractivity p=c1⋅(n-1)+c2⋅(n-1)2+c3⋅(n-1)3+⋯ , via measurement at T = 293.1529(13) K and λ = 632.9908(2) nm for p ≤ 500 kPa. The authors give values of the coefficients c1, c2, c3 for six gases: Ne, Ar, Xe, N2, CO2, and N2O. For each gas, the resulting molar polarizability AR≡2RT3c1 has a standard uncertainty within 16 × 10-6·AR . In these experiments, pressure was realized via measurements of helium refractivity at a known temperature: for He, the relationship between pressure and re

SUBMITTER: Egan PF 

PROVIDER: S-EPMC6760043 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature