title: Potential energy surface, bound states, and rotational inelastic cross sections of the He-CH4 system: a theoretical investigation.
abstract: We determined two potential energy surfaces (PES) for the He-CH(4) system by means of MP4 and Valence Bond (VB) calculations. The MP4 potential is similar to the one commonly adopted for this system [U. Buck, K. H. Kohl, A. Kolhase, M. Faubel, and U. Staemmler, Mol. Phys. 55, 1255 (1985)], while the VB PES is slightly more attractive. To evaluate the reliability of these potentials, we investigated the scattering properties by performing close coupling calculations, and concluded that: (i) the available experimental data do not permit the ranking among the PES considered; (ii) some theoretical predictions differ considerably from the experimental data, and these discrepancies cannot entirely be ascribed to the inaccuracy of the ab initio calculations; (iii) the scattering properties at low energy might discriminate between the MP4 and VB potentials.
authors.affiliation: Dipartimento di Chimica Fisica ed Elettrochimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milan, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Calderoni
authors.forename: F
authors.initials: F
authors.lastname: Cargnoni
authors.forename: R
authors.initials: R
authors.lastname: Martinazzo
authors.forename: M
authors.initials: M
authors.lastname: Raimondi