Rotational Absorption Spectrum of OCS

Extended measurements in the microwave rotational spectrum of carbonyl sulfide (OCS) are presented and correlated with the data obtained by other investigators. Precision measurements of rotational transitions for $J_{1\to 2}$, $J_{2\to 3}$, $J_{3\to 4}$, $J_{4\to 5}$ allow the evaluation of precise reciprocal moments of inertia in the ground vibrational state, and the centrifugal distortion coefficient. From frequencies observed for ${\mathrm{O}}^{16}$ ${\mathrm{C}}^{12}$ ${\mathrm{S}}^{32}$, ${\mathrm{O}}^{16}$ ${\mathrm{C}}^{13}$ ${\mathrm{S}}^{32}$, and ${\mathrm{O}}^{16}$ ${\mathrm{C}}^{12}$ ${\mathrm{S}}^{34}$, internuclear distances have been calculated. Equilibrium moments of inertia and internuclear distances cannot as yet be given, since thus far only one of the three vibrational-rotational interaction coefficients (${\alpha }_2$) has been reported. Theoretical considerations involving such equilibrium data are discussed. Data on $l$-doubling in ${\mathrm{O}}^{16}$ ${\mathrm{C}}^{12}$ ${\mathrm{S}}^{32}$, ${\mathrm{O}}^{16}$ ${\mathrm{C}}^{13}$ ${\mathrm{S}}^{32}$, and ${\mathrm{O}}^{16}$ ${\mathrm{C}}^{14}$ ${\mathrm{S}}^{32}$ are presented. The Stark effect of carbonylsulfide has been measured in ${\mathrm{O}}^{16}$ ${\mathrm{C}}^{12}$ ${\mathrm{S}}^{32}$ and ${\mathrm{O}}^{16}$ ${\mathrm{C}}^{13}$ ${\mathrm{S}}^{32}$. These measurements lead to the evaluation of the dipole moment and indicate the effect of isotopic changes on the dipole moment.