Theoretical studies of the valence electronic states and the 1Πu←X1Σ+g absorption spectrum of the F2 molecule

Publisher Website
Google Scholar
Abstract
The twelve electronic states of F2 dissociating into ground state F(2P) atoms have been investigated with ab initio polarization configuration interaction wave functions. Using a [3s2pld] contracted Gaussian basis, the theoretical spectroscopic constants (with experimental values in parenthesis) for the 1Σ+g ground state are: Re=1.427 Å (1.412 Å), De=1.85 eV(1.66 eV), ωe=946 cm−1 (924 cm−1), and ωexe=−10.6 cm−1 (−22.2 cm−1). The 3Πu state is also found to be very weakly bound (Re=1.881 Å, De=0.15 eV), while the remaining nine electronic states are strictly repulsive (aside from van der Waals minima). Molecular properties are reported for the 1Σ+g state and a detailed analysis of the 1Πu ←1Σ+g absorption is carried out. The 3Πu state appears to be the lower state in the 157 nm laser emission observed recently, which would correspond to the 23Πg→13Πu electronic transition.