Knowledge Bank

The emission spectra of TaN have been investigated in the $9000-25000cm-1$ 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 $N2$. 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. $A\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma +$ state, with equilibrium constants of $Be=0.457907(11)cm-1,\alpha e=0.002350(22)cm-1$ and $re=1.682999(20)$ {\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 $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Delta 1$ state at $2827cm-1$ 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.