The determination of the electric dipole moment of H 2CS in the [formula omitted] excited state using dye-laser electric field spectroscopy

Abstract

An electric field spectrum of thioformaldehyde has been measured for the 4 0 1 vibronic band of the A ̃ 1A 2- X ̃ 1A 1 electronic transition, using a tunable dye laser as the radiation source. Measurements of the Stark splittings of a number of lines in electric fields up to 8.7 kV/cm lead to a value of 0.79 ± 0.04 D for the excited state dipole moment. The decrease of dipole moment on excitation is compared with the equivalent change in formaldehyde and with predictions from ab initio calculations.