Direct-potential-fit analyses yield improved empirical potentials for the ground X-1 Sigma(+)(g) state of Be-2

作者：Meshkov Vladimir V^*; Stolyarov Andrey V; Heaven Michael C; Haugen Carl; LeRoy Robert J

来源：Journal of Chemical Physics, 2014, 140(6): 064315.

DOI：10.1063/1.4864355

We have performed new direct-potential-fit (DPF) analyses of the rotationally resolved A(1)Pi(u) (v' = 2, 3; J' = 1, 2) -> X-1 Sigma g+ (v '' is an element of [0, 11]; J '' is an element of [0, 3]) stimulated emission pumping spectra of Be-2 [J. M. Merritt, V. E. Bondybey, and M. C. Heaven, Science 324, 1548 (2009)] using two quite different analytical potential energy functions that incorporate the correct theoretically known long-range behaviour in different ways. These functions are: the damped Morse/long-range potential [R. J. Le Roy, C. C. Haugen, J. Tao, and H. Li, Mol. Phys. 109, 435 (2011)], and the Chebyshev polynomial expansion potential [L. Busevica, I. Klincare, O. Nikolayeva, M. Tamanis, R. Ferber, V. V. Meshkov, E. A. Pazyuk, and A. V. Stolyarov, J. Chem. Phys. 134, 104307 (2011)]. In contrast with the expanded Morse oscillator potential determined in the original DPF analysis of Merritt et al. [Science 324, 1548 (2009)], both of these functions unambiguously support the existence of the v '' = 11 last vibrational levels which is bound by only similar to 0.5 cm(-1), and they give equivalent, essentially exact predictions for this level when using the original data set which ended at v '' = 10. These empirical potentials predict an equilibrium distance of re = 2.445(5) angstrom and a well depth of D-e = 934.9(0.4) cm(-1), values which agree (within the uncertainties) with the best ab initio estimates of 2.444(10) angstrom and 935(10) cm(-1), respectively [J. Koput, Phys. Chem. Chem. Phys. 13, 20311 (2011)].

• 出版日期2014-2-14