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 carr
ied out in order to complete the available theoretical data in Si,. Th
is affords a consistent interpretation concerning the nature of the N-
3 Sigma(u)(-), O-3 Sigma(u)(-) and P-3 Pi(g) states that had not been
calculated previously. Some controversial bands previously assigned to
Si-2 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.