INFRARED DEPLETION SPECTROSCOPY OF THE ANILINE DIMER

The infrared depletion spectrum of the aniline dimer, formed in a supe rsonic jet, has been recorded in the N-H stretch region by combining i nfrared laser excitation and resonant two-photon ionization/time-of-fl ight mass spectrometry. Only two bands have been found at 3394.0 and 3 465.9 cm(-1) (+/-0.5 cm(-1)) in the region 3130-3530 cm(-1) These are red-shifted by 27.8 and 42.3 cm(-1) from the symmetric and asymmetric NH stretching vibrations of the aniline monomer, respectively, A confi guration with mutual NH2 ...pi bonds and phenyl groups stacked in para llel is suggested for the ground-state aniline dimer.