Knowledge Bank

Gas phase mixtures of $NFCl2$ in argon were excited at 249 nm and 193 nm with an excimer laser. Excitation at 249 nm generated emission bands at 258 nm and 284 nm, assigned to the $D\to A\prime$ transitions in $Cl2$ and CIF. respectively. Excitation at 193 nm generated emission assigned to the $CIF(D\prime ⟶A\prime )$ transition, and emission assigned to transitions in $Cl2$ originating from electronic states that lie above the D' state. Visible emission was also observed following the 193 nm excitation of $NFCI2$. and a likely candidate for this emission is the NFCI radical. The UV absorption spectrum of NFCI radicals isolated in a low temperature argon matrix was measured, and its relationship to the visible emission will be presented. The data indicate that the diatomic halogens and the visible emitter generated are direct photofragments, and that the dissociative $NFCI2$ electronic states accessed at 193 nm and 249 nm correlate to these species.