Relative permittivities and dielectric virial coefficients of nitrogen at T=283.401 K and T=303.409 K determined using a cylindrical microwave cavity resonator

Abstract

A very small and highly stable cylindrical microwave cavity resonator was used to measure the relative permittivities ε of nitrogen at T=283.401 K and T=303.409 K, for pressures up to 4.015 MPa. The total fractional uncertainties in ε at the 0.95 probability level were ±2.2·10 −6 to ±4.2·10 −6 for the cylinder’s TM010 mode, ±3.0·10 −6 to ±4.8·10 −6 for the TM011 mode, and ±9.0·10 −6 to ±9.9·10 −6 for the TM110 mode. The ε measurements were combined with recently published values of the second and third ( p, V m, T) virial coefficients to determine the first dielectric virial coefficients A ε(283.401 K)=(4.3921±0.0018) cm 3· mol −1 and A ε(303.409 K)=(4.3911±0.0016) cm 3· mol −1 , and the second dielectric virial coefficients B ε(283.401 K)=(2.7±1.8) cm 6· mol −2 and B ε(303.409 K)=(2.5±1.6) cm 6· mol −2 , where the uncertainties are at the 0.95 probability level. The second dielectric virial coefficients were used to determine an estimate of the quadrupole moment of nitrogen, Θ=(5.1±2.9)·10 −40 C· m 2 , in agreement with published results obtained using a variety of techniques.