HIGH-RESOLUTION SPECTROSCOPY OF THE S-1[-S-0 ELECTRONIC-TRANSITION OF4-FLUOROSTYRENE IN A MOLECULAR-BEAM

The spectra of the 0(0)(0) and 41(0)(1)42(0)(1) bands in the near-ultr aviolet S-1<--S-0 electronic system of 4-fluorostyrene, formed in a su personic expansion, have been recorded. The individual rotational line s in both bands were resolved and have been completely assigned using a rigid asymmetric rotor Hamiltonian. Both bands were a/b hybrids with the transition moment inclined at an angle of +/- (35(-5)(+4))degrees to the a principle inertial axis. The rotational constants were used to determine effective geometries for the molecule in the S-0 and S-0 states. (C) 1997 Elsevier Science B.V.