Long-range coefficients for the low-lying electronic states of BeLi and Be-2

Using the frequency-dependent dipole polarizabilities calculated for the fi ve lowest states 2 S-1, 2 P-3, 2 P-1, 3 S-3 and 3 S-1 of Be and for the 2 S -2 and 2 P-2 states of Li, from our time-dependent gauge invariant method, estimates of C-6 were obtained for all the first molecular states dissociat ions: 2 S-1 + 2 S-1, 2 S-1 + 2 P-3, 2 S-1 + 2 P-1 and 2 P-3 + 2 P-3 of Be-B e and 2 S-2 + 2 S-1, 2 P-2 + 2 S-1 and 2 P-2 + 2 P-3 of Li-Be. Some higher interactions between these states were also estimated: 2 S-1 + 3 S-1, 3 S-3 + 2 P-3, 2 P-1 + 2 P-1, 3 S-1 + 2 P-1, 3 S-3 + 3 S-3, 2 P-1 + 2 P-3, and 3 S-1 + 3 S-1 for the homonuclear system, 2 P-2 + 2 P-1 and 2 S-2 + 2 P-3 fo r the heteronuclear one. Experimentally, only the (X (1)Sigma(g)(+)) ground state, and the two first (A (1)Pi(u) and B (1)Sigma(u)(+)) states, which d issociate in 2 S-1 + 2 S-1 and 2 S-1 + 2 P-1 channels respectively, are kno wn for Be-2. The long-range coefficients reported for almost all of the low -lying states are new. (C) 1999 American Institute of Physics. [S0021- 9606 (99)30904-1].