Studies of the vapor phase photodissociation of azomethane-d(6)

[摘要] The photodissociation of fully deuterated azomethane into two CD$sb3$ radicals and N$sb2$ was studied using transient CARS spectroscopy as a nanosecond resolved probe of the photoproducts. The Raman-active $usb1$ symmetric C-D stretching band of CD$sb3$ radicals was observed and the following spectroscopic constants were obtained: $usb0$ = 2157.5 cm$sp{-1}$, $Delta$B = $-$0.026 cm$sp{-1}$, $Delta$C = $-$0.018 cm$sp{-1}$, and X$sb{12}$ = $-$5 cm$sp{-1}$. Kinetic observations of the CD$sb3$ photoproducts indicated that azomethane-d$sb6$ photodissociates in a stepwise manner through a methyldiazenyl-d$sb3$ radical intermediate. Indirect observations showed that this intermediate was formed promptly and found to have a lifetime of approximately 7 ns before decomposing into a CD$sb3$ radical and N$sb2$. A spectroscopic examination of N$sb2$ photofragments revealed that their nascent vibrational distribution was 92 $pm$ 5% in v = 0, 8 $pm$ 5% in v = 1, and 0 + 5% in v $>$ 1.

[发布机构] Rice University

[效力级别] chemistry