The lowest-lying Rydberg states of Si2: an ab initio study Original Research Article

SCF-MRCI ab initio calculations of the potential curves of the lowest-lying Rydberg states (between 35 000 and 55 000 cm−1) have been carried out in order to complete the available theoretical data in Si2. This affords a consistent interpretation concerning the nature of the N3Σu−, O3Σu−and P3Πg states that had not been calculated previously. Some controversial bands previously assigned to Si2 cannot be accounted for in the calculations. Spectral positions and intensities are predicted for some perpendicular transitions while it is shown that all parallel transitions with significant intensity seem to have been observed in the spectrum of this molecule.