THE BINDING-ENERGY AND VIBRONIC STRUCTURE OF NBXE+

The resonant photodissociation spectrum of NbXe+ from 13500 to 16400 c m(-1) has been analyzed for the first time. Study of a relatively inte nse electronic transition, dubbed the B-X system, has yielded an elect ronic origin, and the excited state vibrational frequency and anharmon icity: T-00 = 13601, omega(e)' = 85.2, and omega(e)x(e)' = 0.63 cm(-1) . From the convergence of the upper-state vibrational structure and an alogy to isovalent molecules, it is found that NbXe+ dissociates at 16 651 +/- 10 cm(-1) into Nb+ [4d(3)5s(1) (P-5(2))] + Xe(S-1(0)), fragmen ts. This places the diabatic dissociation energies (D-0) of the excite d ((5) Pi(1)) and ground ((5) Sigma(0)(+)) electronic states at 3051 /- 10 cm(-1) and 5815 +/- 10 cm(-1), respectively. (C) 1997 Elsevier S cience B.V.