STABILITY OF BN AND ITS IONS, FROM BN3- - AN AB-INITIO MRD-CI STUDY( TO BN2)

The stabilities of BN and its ions, from BN3+ to BN2-, were investigat ed by ab initio methods. Theory predicts the ground state of BN to be X(3) Pi, with alpha(1) Sigma(+) lying about 0.03 eV higher. Photodetac hment of BN- and photoionization of BN are proposed as alternative rou tes to optical spectroscopy for identifying the ground state of BN. Th e electronic spect a of BN- and BN+ exhibit features similar to those observed for the isoelectronic C-2 ions. BN- and BN+ have low infrared intensities, whereas BN(X(3) Pi) is practically infrared-inactive. Fo urteen electronic states of BN2+ and three of BN3+ are metastable, an uncommonly large number for multiply charged cations from the first ro w. Both high-energy ions might be characterized experimentally by the calculated ionization potentials and kinetic energy releases. Ln the g as phase, the dianion BN2- autodetaches spontaneously into BN- + e(-), but it could be stabilized, e.g., in Li2BN crystals. (C) 1995 John Wi ley & Sons, Inc.