EMISSION SPECTROSCOPY AND AB INITIO CALCULATIONS ON TaN

Author Institution: Department of Chemistry, University of Arizona; Laboratoire de Chimie Physique Mol\'{e}culaire, Universit\'{e} Libre de Bruxelles; Department of chemistry, University of WaterlooThe emission spectra of TaN have been investigated in the $9000-25000 cm^{-1}$ region using a Fourier transform spectrometer. The spectra were observed in a tantalum hollow cathode lamp by discharging a mixture of 1.5 Torr of Ne and about 6 mTorr of $N_{2}$. In addition to previously known bands, numerous additional bands were observed and assigned to a number of new transitions. The spectroscopic properties of the low-lying electronic states of TaN were also predicted by ab initio calculations. $A {^{1}}\Sigma^{+}$ state, with equilibrium constants of $B_{e}=0.457907(11) cm^{-1}, \alpha_{e}=0.002350(22) cm^{-1}$ and $r_{e}=1.682999(20)$ {\AA}, has been identified as the ground state of TaN based on our experimental observations supported by the ab initio results. This state is followed by a $^{3}\Delta_{1}$ state at $2827 cm^{-1}$ above the ground state. The higher energy region consists of several singlet and the triplet states, with the triplet states having Hund's case (c) characteristics. Most of the excited states ($\Omega$ states) are affected by strong interactions with nearby states