Comparison of spectroscopic potentials and an a priori analytical function. The potential energy curve of the ground state of the sodium dimer, X1Sigmag(+) Na2.
The results of a "universal" potential energy function, one that incorporates electronegativity and Slater's effective nuclear charge into a Morse-type function, are compared to spectroscopically derived potential energy curves of the X1Sigmag(+) state of Na2. The function is a priori in that it does not require prior knowledge of the actual potential and has no adjustable parameters. Criteria used to evaluate the performance of the function are comparisons of predicted versus spectroscopic energies at Rydberg-Klein-Rees (RKR) procedure turning points, predicted distances at measured energies versus RKR distances, and eigenvalues derived from the a priori potential versus spectroscopically deduced energy levels. The a priori function describes the Na2 potential with deviations approaching the magnitude of those found among some spectroscopic potentials from different sources. By examining the behavior of the "spectroscopic" parameter of the Morse function, irregularities are found in five of the seven spectroscopic potentials examined. A new procedure is demonstrated for correcting irregularities on the inner branch of spectroscopic potentials at high extents of dissociation and for extending reliably the potential in this region beyond the domain of the measurements.
Matsunaga
Nikita
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Department of Chemistry and Biochemistry, Long Island University, University Plaza, Brooklyn, New York 11201, USA. nmatsuna@liu.edu
Zavitsas
Andreas A
AA