Heterodyne measurements of 12C 18O, 13C 16O, and 13C 18 O laser frequencies; mass dependence of Dunham coefficients

Abstract

Difference frequencies between rare isotope CO lasers and a 12C 16O laser have been measured by optical heterodyne techniques. These data for 12C 18O, 13C 16O, and 13C 18O have been used together with the 15 previously reported Dunham coefficients Y kl for 12C 16O to determine a set of mass independent parameters Δ kl and U kl defined by Y kl = μ -( k/2+ l )[1+ m e(Δ C kl / M C + Δ O kl / M O)] U kl . The 01, 1 0, and 20 correction terms were found to be statistically significant. Line frequencies calculated from the resulting 15 Dunham coefficients for the rare isotopes are accurate to a few MHz in the measured laser bands.