AN AB-INITIO STUDY OF THE TRANSITION MOMENTS, TRANSITION-PROBABILITIES, AND RADIATIVE LIFETIMES OF THE QUARTET STATES OF THE BEN MOLECULE

Transition moments for the quartet states of BeN are calculated at the multi-reference single and double excitations configuration interacti on level using natural orbitals as one-particle basis and an extended set of 98 contracted Cartesian Gaussians. The large shift of almost-eq ual-to 1.2 a0 in the equilibrium distance of the state B 4SIGMA- is ma inly responsible for a continuous character of the spectrum in the UV (almost-equal-to 273 nm) corresponding to B 4SIGMA(-)-X4SIGMA- transit ions which are expected to be relatively intense as suggested by the m agnitude of the transition moment. The A 4PI-X 4SIGMA- transitions are expected to occur in the near IR (lambda10 almost-equal-to 956 nm) an d to be relatively weak (A10 = 5.7 x 10(3) s-1) as a result of the sma ll value of the transition moment. Radiative lifetimes for the state A 4PI are estimated to be of the order of 100 mus. For the B 4SIGMA(-)- A 4PI transition, a maximum intensity in a continuous spectrum in the near UV (almost-equal-to 330 nm) is also predicted. Since no experimen tal results are available, comparisons with similar transitions in C2, O2+, and NO are also presented.