BP is a molecule that, to date, has not been experimentally characterized. However, theoretical calculations yield a stable molecule, although its ground state is not unequivocally determinated. In this work, potential energy curves for the ground state and the lower excited states of BP molecule have been calculated. They are derived using the MRDCI procedure and employing 6-311 +G(2df) basis sets. The spectroscopic constants and excitation energies for the bound states of BP are compared with previous theoretical results. The MRDCI calculations give the (II)-I-3 state as the ground state, with R-e = 1.747 Angstrom, D-e = 3.15 eV and omega(e) = 954 cm(-1). (C) 2003 Elsevier B.V. All rights reserved.