Rotational spectrum of HCBr produced by 193-nm laser photolysis of bromoform

Abstract

The pure rotational spectrum of bromomethylene (HCBr) was studied by kinetic microwave spectroscopy between 420 and 472 GHz. The HCBr radical was produced by 193-nm ArF laser photolysis of bromoform (CHBr 3). More than 130 rotational transitions for both HC 79 Br and HC 81 Br species in the ground vibrational state were measured involving 1⩽ J⩽33 and 0⩽ K a ⩽5. The spectra were well described by an S-reduced Watson Hamiltonian in the I r representation including the nuclear quadrupole and spin-rotation hyperfine terms. Rotational, centrifugal distortion, 79,81 Br nuclear quadrupole and spin-rotation coupling constants were derived for both HC 79 Br and HC 81 Br species in the ground vibrational state.