Ab Initio Diabatic energies and dipole moments of the electronic states of RbLi molecule

For all states dissociating below the ionic limit Li− Rb+, we perform a diabatic study for 1Σ+ electronic states dissociating into Rb (5s, 5p, 4d, 6s, 6p, 5d, 7s, 4f) + Li (2s, 2p, 3s). Furthermore, we present the diabatic results for the 1–11 3σ, 1–8 1,3Π, and 1–4 1,3Δ states. The present calculations on the RbLi molecule are complementary to previous theoretical work on this system, including recently observed electronic states that had not been calculated previously. The calculations rely on ab‐initio pseudopotential, core polarization potential operators for the core‐valence correlation and full valence configuration interaction approaches, combined to an efficient diabatization procedure. For the low‐lying states, diabatic potentials and permanent dipole moments are analyzed, revealing the strong imprint of the ionic state in the 1Σ+ adiabatic states. The transition dipole moment is used to evaluate the radiative lifetimes of the vibrational levels trapped in the 2 1Σ+ excited states for the first time. In addition to the bound–bound contribution, the bound–free term has been evaluated using the Franck–Condon approximation and also exactly added to the total radiative lifetime. © 2013 Wiley Periodicals, Inc. The calculation of the radiative lifetimes is carried out using Fermi's golden rule. The determined radiative lifetimes of the vibrational levels trapped in the 21Σ1+ state have an order of magnitude of nanoseconds. For this state, as the vibrational level increases, the radiative lifetime presents some oscillations; however, these are much weaker than for the nonradiative lifetime in which orders of magnitude vary.