15min:

DOMINIQUE R. T. APPADOO, ALIREZA SHAYESTEH, PETER F. BERNATH AND ROBERT J. LE ROY, Guelph-Waterloo Centre for Graduate Work in Chemistry and Biochemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.

Some years ago Learner recorded electronic spectra involving the A ^{1 +} state of AgH, and found anomalous behaviour of the vibrational level spacings and B_v values which he attributed to the potential energy curve for this state having a ``shelf''. More recently, Witek et al. reported ab initio results which supported Learner's assertion that the potential energy function for this state had an unusual shape, but found that rather than have a shelf, there was an abrupt stiffening of the bond for vibrational levels above v\!~\!4 . In order to clarify this situation, we have combined new and previously recorded visible A\!-\!X spectra and high quality microwave and infrared data for ^107/109AgH and ^107/109AgD in a combined-isotopomer direct-potential-fit analysis which determines analytic potential energy and Born-Oppenheimer breakdown functions for this state. A similar approach is used to study the analogous A ^{1 +} state of ^63/65CuH and ^63/65CuD.