VIBRONIC ANALYSIS OF INDOLE AND 1H-INDOLE-D6

The excitation spectra of indole and indole-2,3,4,5,6,7-d6 have been o btained with jet-cooled one-color resonant two-photon ionization (1C R 2PI) time-of-flight mass spectrometry (TOFMS). The deuterated indole s pectra 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 o f Bickel et al.5 as a guide for the deuterated species and an ab initi o ground-state vibrational calculation of both species. This calculati on was obtained by using Gaussian 90, from which the excited-state fre quencies of the deuterated species have been estimated from the known excited-state normal protonated values. Comparison of both excited-sta te vibronic spectra has shown an essentially 1:1 correspondence betwee n all of the bands, suggesting that there is no significant band in th e indole spectrum in this interval which can uniquely be assigned as b elonging to a system other than the L-1(b) <-- 1A' transition.