A vacuum ultraviolet laser single-photon zero kinetic energy photoelectron spectroscopic study of the 2E3/2 ground electronic state of CH3Br+

The vacuum ultraviolet laser single-photon zero kinetic energy (ZEKE) photoelectron spectrum of the [Formula: see text]2E3/2 ground electronic state of the methyl bromide cation is reported. The spectrum is dominated by the origin band 000 of the transition [Formula: see text]2E3/2 ← [Formula: see text]1A1. In addition, the 210 band and the 311 hot band are observed. All observed bands show similar rotational contours. Simulation of the rotational contour of the origin band yields the first ionization energy of methyl bromide (85 031.2 ± 1.0 cm–1) and the rotational constants of the cation in its ground electronic state. Key words: methyl bromide, vacuum ultraviolet laser, single-photon excitation, zero kinetic energy photoelectron spectroscopy.