title: Theoretical Study of BeN Linear Chains: Optimized Geometries and Harmonic Frequencies.
abstract: The electronic structure of linear beryllium chains has been theoretically studied at an ab initio level. By using a CAS-SCF approach, geometries have been optimized and harmonic frequencies computed. The optimized geometries present almost equal bond lengths, while all the harmonic frequencies are real. This fact indicates the presence of a local minimum, at this level of theory, having a linear geometry. The energy splitting between the singlet ground state, (1)Σg, and the quasi-degenerated excited triplet, (3)Σu, has been computed at CAS-SCF and MR-CI level. It was found that the splitting goes exponentially to zero as the number of atoms in the chain is increased.
authors.affiliation: Dipartimento di Chimica Fisica e Inorganica, Università di Bologna Viale Risorgimento 4, I-40136 Bologna, Italy.|Laboratoire de Chimie et Physique Quantiques, Université de Toulouse et CNRS, 118, Route de Narbonne, F-31062 Toulouse Cedex, France.
authors.forename: Antonio
authors.initials: A
authors.lastname: Monari
authors.affiliation: Dipartimento di Chimica Fisica e Inorganica, Università di Bologna Viale Risorgimento 4, I-40136 Bologna, Italy.|Laboratoire de Chimie et Physique Quantiques, Université de Toulouse et CNRS, 118, Route de Narbonne, F-31062 Toulouse Cedex, France.
authors.forename: Gian Luigi
authors.initials: GL
authors.lastname: Bendazzoli
authors.affiliation: Dipartimento di Chimica Fisica e Inorganica, Università di Bologna Viale Risorgimento 4, I-40136 Bologna, Italy.|Laboratoire de Chimie et Physique Quantiques, Université de Toulouse et CNRS, 118, Route de Narbonne, F-31062 Toulouse Cedex, France.
authors.forename: Stefano
authors.initials: S
authors.lastname: Evangelisti