15min:

L. A. KALEDIN, A. L. KALEDIN, M. C. HEAVEN, Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, GA 30322; V. E. BONDYBEY, Institut fur Physikalische und Theoretische Chemie der TU Munchen, W-8046 Garching, Germany.

~~~~Low-lying electronic states of Be₂ have been examined using laser excitation techniques. The dimer was formed by pulsed laser ablating Be into a free-jet expansion. Dimer formation was enhanced by liquid nitrogen cooling of the nozzle assembly.

~~~~Dispersed fluorescence spectra were recorded following excitation of various vibrational levels of the B~¹\stackrel⁺_u state. These spectra revealed bands of the previously unobserved B~¹\stackrel⁺_u\longrightarrowA'~¹_gtransition. The term energy (T₀=13,942\underline+20cm^-1) and vibrational interval G_1/2 =717\underline+20cm^-1) for the A' state were determined for the first time.

~~~~Potential energy curves and electronic transition moments for Be₂ were calculated using EOM coupled cluster and MRSDCI levels of theory with a (12s6p3d2f1g)/[5s4p3d2f1g] basis set. The properties of low-lying singlet, triplet, and quintet states were predicted. The MRSDCI results were found to be in excellent agreement with experimental observations