VIBRONIC ASSIGNMENTS OF THE S-1-]S-0 EMISSION-SPECTRUM OF THE JET-COOLED P-FLUOROTOLUENE

The p-fluorotoluene was vibronically excited in a jet with a buffer ga s He in a corona excited supersonic expansion. The vibronic emission s pectrum of the jet cooled p-fluorotoluene in the transition of S-1 --> S-0 has been recorded with a Fourier transform spectrometer in the uv region. The spectrum observed was analyzed to obtain accurate vibrati onal frequencies in the ground electronic state by comparing with thos e reported previously. The origin of the low frequency sequence bands observed in this work was discussed. Also, the absence of significant intensity of hot band resulting from the excited vibrational states in the spectrum suggests extensive vibrational cooling in the source.