Knowledge Bank

The emission spectrum of RuN has been observed in the near infrared using a Fourier transform spectrometer. RuN molecules were excited in a hollow cathode lamp operated with neon gas and a trace of nitrogen. Two bands with 0-0 Q heads near 7354 and $8079cm-1$ and a common lower state have been assigned as $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Pi 1/2-\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma +$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Pi 3/2-\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma +$ subbands, respectively, of a $A\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Pi -X2\Sigma +$ transition. A rotational analysis of these bands has been performed and molecular constants have been extracted. The principal molecular constants for the ground $X2\Sigma +$ state of the most abundant $\mathrm{<mrow\; data-mjx-texclass="ORD">102</mrow>}RuN$ isotopomer are: $B0=0.5527738(99)cm-1,D0=5.511(19)\times 10\ast \ast \ast cm-1,\gamma 0=-0.044401(30cm-1)$ and $r0=1.573882(14)${\AA}. The excited $A2\Pi$ state has the following molecular constants: $T\infty =7714.34082(66)cm-1,A0=725.8031(13)cm-1,B0=0.516818(11)cm-1,D0=5.664(67)\times 10-2cm-1,p0=5.446(46)\times 10\ast \ast \ast cm-1$ and $r0=1.627710(17)${\AA}. Ab initio calculations have been carried out on RuN to assertain the nature of the experimentally observed states and predict the spectroscopic properties of the low-lying electronic states. Our electronic assignment is supported by these calculations and is also consistent with the observations for the isoelectronic RhC molecule [Kaving and Scullman, J. Mol. Spectrosc. 32, 475-500 (1969)]. The valence electron configuration $1\sigma 22\sigma 21\pi 41\delta 43\sigma 1$ is proposed for the $X2\Sigma +$ ground state of RuN and the configurations for the excited states have been discussed. There is no previous experimental or theoretical work on RuN.