Determination of the electric dipole moment of the HSO radical in its X̃2A″(000) and Ã2A′(003) electronic states

Abstract Stark shifts were measured for the zero-field-allowed 0 00 -1 10 , 1 10 -0 00 and zero-field-forbidden 0 00 -1 11 , 1 11 -0 00 lines of the HSO A 2 A′(003)- X 2 A″(000) transition. A single-mode dye laser is used to record the Doppler-limited fluorescence excitation spectrum as a function of applied electric field (0–11 kV/cm) for excitation polarizations parallel and perpendicular to the applied field direction. The electric dipole moment along the a axis of this near-prolate asymmetric top is determined to be μ ″ a = 2.20 ± 0.08 D and μ ′ a = 1.05 ± 0.08 D, in close agreement with recent ab initio calculations.