Jet-cooled optical spectroscopy of FeN between 16 300 and 21 600 cm-1

We report the first gas-phase spectroscopic study of iron mononitride (FeN). FeN molecules were generated by the reaction of laser-ablated Fe atoms with NH3 under supersonic jet-cooled conditions. Laser-induced fluorescence excitation spectra were measured between 16 300 and 21 600 cm-L, and rotational analyses have been performed for about 25 vibronic bands. The Omega value of the ground state has been determined to be 5/2, which could be the spin-orbit component of (2)Delta (...1 delta (3)9 sigma (2)) or (4)Pi (...1 delta (3)9 sigma (1)4 pi (1)). The excited states in the visible absorption region show very complicated rovibronic structures due to heavy perturbations. Excited state lifetimes, (FeN)-Fe-56-N-14/(FeN)-Fe-56-N-15 isotope shifts, and dispersed fluorescence spectra were measured for the majority of the bands, which were classified into the five Omega = 5/2-X Omega = 5/2 band systems. (C) 2000 Academic Press.