New Assignments in the Green and Red Band Systems of the FeH Radical

The electronic spectrum of FeH in the regions of the 532 nm (green) and 630 nm (red) systems has been investigated using the techniques of dispersed and undispersed laser induced fluorescence. Sixteen lines have been assigned in the Omega = 1/2 <-- Omega = -1/2 subband of the e6Pi-c6Sigma+ transition and term values determined for the previously uncharacterized e6Pi1/2 spin-orbit component. A further fourteen lines were assigned to the connected Omega = 1/2 <-- Omega = 3/2 subband of the e6Pi-a6Delta transition and term values for the hitherto uncharacterized a6Delta3/2 component were determined. A study of the high-temperature spectrum of FeH, recorded previously by McCormack and O'Connor (1), enabled the branches of the Omega = 7/2 <-- Omega = 9/2 subband of the e6Pi-a6Delta transition to be extended to higher J values. These predictions were confirmed by laser induced fluorescence (LIF) experiments and led to the assignment of 13 additional lines in this subband. The term values for the e6Pi7/2 and a6Delta9/2 spin-orbit components were thus extended to higher J values. Copyright 1998 Academic Press.