The negative ion BN−and its role in determining the ground state of BN via photodetachment. An MRDCI ab initio study

Abstract

Extensive multireference CI calculations using a contracted 6s5p3d1f Gaussian basis set on the B and N atoms indicate that the X2∑+, A2Π, and B2∑+ states of BN− are bound with respect to the electron attachment BN + e−. The 14∑+, 14Δ, 14∑−, and 14Π states of BN− are resonant states, all autodetaching into neutral BN. The electron affinity X3Π → X2∑+ is predicted to be 2.84 eV (with a best estimate of 3.10 eV). Other features studied for BN− include the infrared spectrum of the X2∑+ ground state as well as the electronic radiative properties involving the excited states A2Π and B2∑+. The present study supports a X3Π ground state for BN, with a1∑+ lying about 0.03 eV higher. As an alternative to optical spectroscopy on BN, experimental studies of the photodetachment spectrum of BN− are proposed in order to find the ordering and energetic separation of the lowest 3Π and 1∑+ states of BN.