Infrared depletion spectroscopy of the aniline-H2O+ cluster cation

The vibrational spectrum of the aniline-H2O+ cluster cation in the NH and OH stretching vibration region has been measured as depletion of the ion signal induced by the infrared multiphoton decomposition of the cluster cation. Three absorption bands have been observed at 3440, 3636 and 3715 cm−1, which have been assigned to the free NH stretching vibration of the aniline molecule, the symmetric and the anti-symmetric stretching vibrations of H2O, respectively. The analysis of the spectrum suggests that there is a hydrogen bond between one of the NH bonds of the aniline cation and the lone pair of the oxygen atom of H2O.