LASER INDUCED FLUORESCENCE SPECTROSCOPY OF JET-COOLED IRON MONOCARBIDE: A ${^{3}}\Delta_{1} \leftarrow {^{3}}\Delta_{1}$ TRANSITION NEAR 493nm

Abstract

We report laser induced fluorescence (LIF) spectroscopy of iron monocarbide $(Fe^{12}C, Fe^{13}C)$. To our knowledge, this is the first report of gas phase data on this 3d transition metal monocarbide. FeC was generated in a laser vaporization molecular beam source[1]. Vibronic bands have been recorded for $\nu^{\prime}=0.4$ from $V^{\prime\prime}=0$, in the region from 430 to 500nm. The R-head of the $Fe^{12}C 0-0$ band lies near 493.1nm. Rotational analyses have been performed which indicate that the electronic transition is $^{3}\Delta_{i} \leftarrow ^{3}\Delta_{i}$. No theoretical studies of FeC spectra have been published, however, according to ab initio calculations for the isovalent RuC[2], the ground state of FeC should be a ${^{3}}\Delta_{1}$ state arising from a $1\delta^{3}9\sigma^{1}$ electronic configurations Strong perturbations of the upper state have been observed for several bands.