Knowledge Bank

The investigation of the $\gamma$ and $\beta$ systems of NS molecule has been carried out in emission by using a Littrow type quartz spectrograph and a two meter normal incidence vacuum spectrograph. Nitrogen was flowed continuously through a discharge tube containing sulphur. The tube was heated in such a way as to give the maximum intensity of the NS bands and to avoid the appearence of sulphur and nitrogen bands. The $\gamma$ system $(2\Sigma -\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Pi )$, in which only the bands having $v\prime =0$ were known previously, has been extended to $v\prime =4$, thus giving the vibrational constants for the upper state. The bands with $v\prime =2,3$ and 4 show some irregularity indicating perturbation in the upper state. The $\beta$ system ($\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Delta -\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Pi$) has also been extended. The constants for the $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Delta \ast \ast 2\Pi \ast \ast$ transition have been slightly modified. Four new systems have been observed in the ultraviolet and in the vacuum ultraviolet regions. The details of the vibrational analysis for the $\gamma$ and $\beta$ systems along with some discussion regarding the new systems will be presented in the paper.