A vacuum ultraviolet laser single-photon zero kinetic energy photoelectron spectroscopic study of the (X)over-tilde2E3/2 ground electronic state of CH3Br+

The vacuum ultraviolet laser single-photon zero kinetic energy (ZEKE) photoelectron spectrum of the (x) over tilde E-2(3/2) ground electronic state of the methyl bromide cation is reported. The spectrum is dominated by the origin band 0(0)(0) of the transition (x) over tilde E-2(3/2) <-- (x) over tilde (1)A(1). In addition, the 2(0)(1) band and the 3(1)(1) 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.