Magnetic Susceptibility Anisotropy, Molecular Quadrupole Moment, and the Sign of the Electric Dipole Moment in OCS

Abstract

The molecular Zeeman effects of 16O12C32S and 16O12C34S have been observed under high resolution in magnetic fields up to 30 000 G. Conventional microwave spectroscopy is combined with a 6-ft long magnet to yield accurate first- and second-order magnetic field parameters. The magnetic susceptibility anisotropy of the OCS molecule is χ⊥–χ∥ = (9.27 ± 0.10) × 10−6erg/G2·mole. The molecular g values for the two isotopes obtained from the J = 0 → J = transitions are g⊥(16O12C32S) = − 0.028711 ± 0.00004 and g⊥(16O12C34S) = − 0.028127 ± 0.00004. These data yield the sign of the molecular electric dipole moment which has −OCS+ polarity. Combining χ⊥–χ∥ and g⊥(16O12C32S) gives the molecular quadrupole moment of Q∥(16O12C32S) = − (0.88 ± 0.15) × 10−26esu·cm2.