The $J=1\mathrm{}\to 2$ rotational absorption transition in OCS has been observed for the molecules containing ${\mathrm{S}}^{35}$ and ${\mathrm{S}}^{34}$. From the frequencies, the frequency differences, and the previously known frequencies of ${\mathrm{S}}^{34}$, ${\mathrm{S}}^{33}$, and ${\mathrm{S}}^{32}$ we have evaluated the mass difference ratios (${\mathrm{S}}^{35}$-${\mathrm{S}}^{32}$)/(${\mathrm{S}}^{34}$-${\mathrm{S}}^{32}$) and (${\mathrm{S}}^{35}$-${\mathrm{S}}^{32}$)/(${\mathrm{S}}^{33}$-${\mathrm{S}}^{32}$). From these values and values of the stable S masses two independent values of the (${\mathrm{S}}^{35}$-${\mathrm{S}}^{32}$) mass differences are calculated to be 2.99844±0.00042 and 2.99770±0.00048, respectively.

• Received 30 November 1950

DOI:https://doi.org/10.1103/PhysRev.81.948