Vibrational predissociation dynamics of the aniline-neon van der Waals complex: an ab initio study

The aniline-neon van der Waals complex has been investigated from a theoretical point of view. The intermolecular distance.. structure and rotational constants in the ground electronic state have been obtained by ab initio calculations using second-order Moller-Plesset (MP2) theory. The potential energy surface has also been determined. It has been found that two conformers exist: the anti. where the neon atom and the NH bonds are located on opposite sides of the ring, is slightly more stable than the syn conformer. All the ab initio results agree with those obtained by the analysis of the rotational and laser induced fluorescence spectra of this complex. We have also modeled the interaction of the van der Waals bending mode with others internal motions of the aniline molecule such as the inversion mode of the amino group and the breathing mode of the ring. The theoretical results predict that there is a significant coupling between the van der Waals bending and the inversion mode in agreement with the experimental behavior found in both the around and the first excited electronic states of this complex.