VIBRONIC ANALYSIS OF INDOLE AND 1H-INDOLE-D6

The excitation spectra of indole and indole-2,3,4,5,6,7-d6 have been obtained with jet-cooled one-color resonant two-photon ionization (1C R2PI) time-of-flight mass spectrometry (TOFMS). The deuterated indole spectra have been vibronically analyzed in the region 0(0)0 to 0(0)0 + 904 cm-1 using the single vibronic level fluorescence (SVLF) results of Bickel et al.5 as a guide for the deuterated species and an ab initio ground-state vibrational calculation of both species. This calculation was obtained by using Gaussian 90, from which the excited-state frequencies of the deuterated species have been estimated from the known excited-state normal protonated values. Comparison of both excited-state vibronic spectra has shown an essentially 1:1 correspondence between all of the bands, suggesting that there is no significant band in the indole spectrum in this interval which can uniquely be assigned as belonging to a system other than the L-1(b) <-- 1A' transition.