Rational Isomers and Internal Rotation of the CH3 Group in S0, S1, and Ion of o-Cresol

Article abstract of DOI:10.1021/j100346a031

The fluorescence excitation, dispersed fluorescence, and two-color photoionization spectra have been measured for jet-cooled o-cresol.The cis and trans isomers were identified, and the potential energy curve of the internal rotation of the methyl group was determined in the S₀, S₁, and ionic states.The hindered methyl internal rotation in the S₀ state becomes an almost free rotation in the S₁ state, which becomes hindered again by an ionization.The results are compaed with those of m-cresol.