Determination of the structure of HBr OCS

Abstract

The structure of the HBr OCS van der Waals complex has been studied by Fourier transform microwave spectroscopy. The ground state complex is hydrogen bound and quasilinear with SCO–HBr atomic ordering. Spectra from five different isotopomers were observed and assigned. The wide amplitude bending angle of the hydrogen bromide was calculated from the nuclear quadrupole coupling constant χaa to be 25.2°. Second order quadrupole effects, centrifugal distortion in the nuclear quadrupole coupling constant Dχ, a spin–rotation interaction, CBr, and a spin–spin interaction, Daa, were all included in the Hamiltonian. The following spectroscopic constants have been determined for the H79Br OCS isotopomer: B̄=488.7948(4) MHz; DJ=2.167(6) kHz; HJ=1.19(3) Hz; χaa=387.14(1) MHz; Dx=6.79(14) kHz; CBr=0.55(13) kHz; and Daa=7.7(1.2) kHz.