Abstract: | An extended geminal model has been applied to determine the interatomic potential for the X1Σ state of Be2. By adopting a (23s, 10p, 8d, 6f, 3g, 2h) uncontracted Gaussian‐type basis, the following spectroscopic parameters are obtained: Re = 4.633 a.u. (4.63 a.u.), De = 945 ± 15 cm (790 ± 30 cm), G(1)–G(0) = 221.7 cm?1 (223.8 ± 2 cm?1), G(2)–G(1) = 175.0 cm?1 (169 ± 3 cm?1), G(3)–G(2) = 123.1 cm?1 (122 ± 3 cm?1), and G(4)–G(3) = 80.8 cm?1 (79 ± 3 cm?1), experimental values in parentheses. The calculated binding energy is substantially higher than the accepted experimental value. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 |