LASER VAPORIZED SPECTRA OF A NEW RED SYSTEM OF SiN

Abstract

The spectrum has been recorded for first time in the region 575 - 940 nm along with known blue-green systems using second harmonic of pulsed Nd: YAG laser for vaporization of rotating SiN target inside the ablation chamber and computer controlled Spex TRIAX 320 m monochromator fitted with TE cooled ICCD as a detector. It consists of 50 new bands assigned to $\Delta v = 0, \pm 1, \pm 2, -3, -4$ and $-5$ sequences a new band system with (0,0) band lying at 787 nm. The lower state vibrational constants are same as that of A$^2\Pi$ state reported by earlier workers. The vibrational constants of upper excited state are as follows: \vspace{1em} \begin{tabular}{ccc} $v_e= 12752.4$ cm$^{-1}$ & $\omega_e^\prime = 945.3$ cm$^{-1}$ & $\omega_e^\prime$x$_e^\prime=6.20 $ cm$^{-1}$\\ & $\omega_e^{\prime\prime} = 1044.4$ cm$^{-1}$ & $\omega_e^{\prime\prime}$x$_e^{\prime\prime}=6.26 $ cm$^{-1}$ \end{tabular}