title: Bonding in negative ions: the role of d orbitals in the heavy analogues of pyridine and furan radical anions.
abstract: We have used a potential wall method to investigate the role of d orbitals in the a(2) singly-occupied molecular orbitals of (2)A(2) negative ion states of two molecular series: pyridine, phosphabenzene, arsabenzene, stibabenzene (C(5)H(5)X, X = {N, P, As, Sb}), and furan, thiophene, selenophene, tellurophene (C(4)H(4)X, X = {O, S, Se, Te}). Unlike for the lower lying doubly occupied orbitals, heteroatom d-carbon p in-phase (bonding) interactions in these a(2) orbitals are clearly identified and explain the 0.5 eV stabilization of the (2)A(2) radical anion state in those compounds where the heteroatoms have d orbitals in the valence shell, compared to compounds where d orbitals are missing in the valence shell of the heteroatoms. The performance of both the potential wall approach and the approximate expression of Tozer and De Proft for calculating negative electron affinities has been also investigated, through a comparison with results obtained using electron-transmission spectroscopy experiments.
authors.affiliation: Eenheid Algemene Chemie (ALGC), QCMM Research Group-Alliance Ghent-Brussels, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium. hajgato@vub.ac.be
authors.forename: Balázs
authors.initials: B
authors.lastname: Hajgató
authors.forename: Frank
authors.initials: F
authors.lastname: De Proft
authors.forename: Dénes
authors.initials: D
authors.lastname: Szieberth
authors.forename: David J
authors.initials: DJ
authors.lastname: Tozer
authors.forename: Michael S
authors.initials: MS
authors.lastname: Deleuze
authors.forename: Paul
authors.initials: P
authors.lastname: Geerlings
authors.forename: László
authors.initials: L
authors.lastname: Nyulászi