Long-range coefficients for the low-lying electronic states of BeLi and Be2

Abstract

Using the frequency-dependent dipole polarizabilities calculated for the five lowest states 2 1S, 2 3P, 2 1P, 3 3S and 3 1S of Be and for the 2 2S and 2 2P states of Li, from our time-dependent gauge invariant method, estimates of C6 were obtained for all the first molecular states dissociations: 2 1S+2 1S, 2 1S+2 3P, 2 1S+2 1P and 2 3P+2 3P of Be–Be and 2 2S+2 1S, 2 2P+2 1S and 2 2P+2 3P of Li–Be. Some higher interactions between these states were also estimated: 2 1S+3 1S, 3 3S+2 3P, 2 1P+2 1P, 3 1S+2 1P, 3 3S+3 3S, 2 1P+2 3P, and 3 1S+3 1S for the homonuclear system, 2 2P+2 1P and 2 2S+2 3P for the heteronuclear one. Experimentally, only the (X 1Σg+) ground state, and the two first (A 1Πu and B 1Σu+) states, which dissociate in 2 1S+2 1S and 2 1S+2 1P channels respectively, are known for Be2. The long-range coefficients reported for almost all of the low-lying states are new.