On the dissociation energy of BH

The dissociation energy D(0) of the X 1Sigma(+) state has been determined to be 81.5 + or - 0.5 kcal/mol. This value includes an estimate for basis set incompleteness and for core-core and core-valence correlation. The barrier in the A 1Pi state potential is estimated to be 1.9 + or - 0.2 kcal/mol. By analyzing the tunneling through the barrier, it is demonstrated that D(0) and the predissociation limit differ by about 0.8-0.9 kcal/mol. Thus the experimental predissociation limit of 82.5 + or - 0.4 kcal/mol is consistent with the values computed for D(0) and the barrier in this work.