Near infrared photodissociation spectra of the aniline+-argon ionic complexes

The near infrared spectra of the ionic complexes aniline(NH2)+-argon and aniline(ND2)+-argon have been measured by laser photodissociation spectroscopy. The bands observed from 10 500 to 13 500 cm−1 have been assigned to the D1(A∼2A2)←D0(X∼2B1) electronic transition within the solvated chromophore. They are characterized by a long vibrational progression involving the 6a mode. On the basis of CASSCF calculations, a large change of geometry along this coordinate is found while the amino group remains in the ring plane. Therefore, a change of the conjugation of the ring rather than a charge transfer is inferred. This is thought to be the origin of the extent of the progression.