Journal of Physical Chemistry, Vol.98, No.16, 4261-4270, 1994
Vibronic Analysis of 4-Fluoroindole, 5-Fluoroindole, and 6-Fluoroindole
The excitation spectra of 4-, 5-, and 6-fluoroindole have been obtained with jet-cooled one-color resonant two-photon ionization (1C R2PI) time-of-flight mass spectrometry (TOFMS). The 1C R2PI spectra have been vibronically analyzed in the spectral region of 0(0)(0) to 0(0)(0) + 842 cm(-1) in 4-fluoroindole and 0(0)(0) to 0(0)(0) + similar to 1100 cm(-1) in 5- and 6-fluoroindole. All transitions observed in the 4-, 5-, and 6-fluoroindole excitation spectra are assigned as (1)L(b) <-- (1)A’ transitions. Assignments of both ground- and excited-state vibrational modes were based upon those previously assigned for indole.(4,9) As with indole, the ground-state vibrational frequencies were also calculated using ab initio methods as well as being obtained from infrared and Raman studies.