Abstract

Chemically generated electronically excited species are of interest because of potential applications in short wavelength chemical lasers. Thermal decomposition of FN₃ using ~1-J/cm² CO₂ laser pulses in the presence of SF₆ has generated metastable NF(a) very efficiently.¹ This is attributed to a low energy barrier to dissociation arising from the extremely weak FN—N₂ bond and to a spin constraint which allows only singlet dissociation products from the ground state FN₃. Since these considerations also apply to CIN₃ its decomposition is expected to yield NCl(a) efficiently. Coproduction of NCl(a) along with NF(a) may then be used to pump lasants such as NF(b) or IF(B) by resonant energy pooling reactions. Therefore, dissociation of CIN₃ has been investigated in similar conditions suitable to FN₃ dissociation. The products were found by emission spectroscopy to be NCl(a) and NCl(b). Time-resolved UV absorption of CIN₃ showed that the rate coefficient of CIN₃ dissociation is approximately half of that for FN₃ implying a higher dissociation energy barrier for CIN₃. This result is expected because of lower electronegativity of the Cl-atom and the consequently stronger CIN—N₂ bond. The yield of NCl(a) radicals has been found by absolute photometry to be near unity.

© 1990 Optical Society of America