Anion photoelectron spectroscopy of B3N

to the linear P and S electronically excited states of neutral B3N, with all three states having a B–N–B–B structure. Weak signal observed at lower electron binding energies is tentatively assigned to two additional linear-to-linear transitions from the low-lying electronically excited P state of B3N 2 to the S and P states of neutral B3N. Based on these assignments the electron affinity of linear B–N–B–B is 2.09860.035 eV. It remains uncertain if the S state of linear B–N–B–B or the A1 state of cyclic B3N is the overall ground state. At the highest level of theory used here, CCSD~T!/aug-cc-pVTZ, the S state is predicted to lie 0.09 eV below the A1 state. © 1999 American Institute of Physics. @S0021-9606~99!00746-1#