Vibronic analysis of substituted indoles

he excitation spectra of indole and several substituted indole molecules (analogs of the amino acid, tryptophan) were obtained using the experimental technique of supersonic jet one color (1C) resonant two-photon ionization (R2PI) time-of-flight mass spectrometry. Ground state fundamental vibrational modes of the substituted indoles were assigned by comparison to those of indole based on experimental (IR and Raman spectra) and theoretical (ab initio) data. As a basis of study, the excitation spectra of indole (-h7) and indole (-d6,h1N) were obtained and the vibronic bands were assigned in the spectral region of 0;The excitation spectra of tryptamine and serotonin (5-hydroxytryptamine) were also obtained using the same experimental technique. The specific geometries of tryptamine and serotonin conformers, observed as several origin transitions in the low frequency region of the excitation spectra, were predicted through theoretical (ab initio) calculations. Ground state fundamental vibrational modes were assigned using both experimental (IR and Raman spectra) and theoretical (ab initio) data and tentative excited state vibronic assignments were made by direct comparison to those of indole.;The low resolution 1C R2PI rotational contours of indole and several substituted indole molecules were obtained. Transition moments for three possible transitions (HOMO...