2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/18637The complex interplay among on-site energy, Hubbard U, and coupling to Holstein and Peierls phonons at the neutral-ionic phase transition is discussed using diagrammatic valence bond calculations. The charge transfer and dimerization amplitudes and the infrared intensity of molecular vibrations are studied in the transition region.6 pages, 2 figures, conference ISCOM 2001Condensed Mattertext