15min:
THE ELECTRONIC STATES AND VIBRATIONAL FUNDAMENTALS OF THE NITRIC OXIDE DIMER, (NO)2, AND DIMER CATION, (NO)2+.

ALLAN L. L. EAST, Department of Chemistry, The University of Akron, Akron, Ohio 44325-3601.

The weakly-bound nitric oxide dimer, with dissociation energy D0 = 2.1 kcal mol-1, is over 7 times more strongly bound than the carbon monoxide dimer, due to unusual partial covalent bonding. Using CASSCF and MRCISD calculations, the lowest 8 states are computed to lie within a 1 eV span, corresponding to electronic excitations in the infrared. As well, coupled-cluster CCSD(T) calculations of the vibrational fundamentals of (NO)2 and (NO)2+ were performed, which aided both (i) the spectroscopic detection of the previously unknown gas-phase fundamentals of the neutral, and (ii) the interpretation of the ZEKE photoionization spectrum obtained a few years ago.