Knowledge Bank

Alkoxy radicals are atmospherically important species, playing a direct role in the HO and NO cycles that affect tropospheric air pollution. Alkoxy radicals that can form a six membered transition state can isomerize into a hydroxyalkyl radical. In the presence of O$2$, a rapid association reaction occurs, forming a hydroxyalkylperoxy radical. The \textit{n}-butoxy radical is the smallest alkoxy to undergo isomerization, forming the $\gamma$-hydroxybutylperoxy radical (HOC$4$H$8$OO). Direct detection of HOC$4$H$8$OO opens the door to measuring alkoxy reaction kinetics with higher precision than previous end product studies. \textbf{2006}, \textit{6}, 3625.} In this talk, we report the first detection of the ~{A}-~{X} electronic spectrum of the HOC$4$H$8$OO radical. The spectrum is similar in shape to the ~{A}-~{X} spectrum of \textit{n}-butyl peroxy: \textbf{2005}, \textit{109}, 11191.} a broad spectroscopic band due to the multiple molecular conformers that are present. We also use the ~{A}-~{X} band to measure the alkoxy isomerization kinetics relative to the alkoxy radical's reaction with O$2$, similar to the previous kinetics studies. Alkoxy radicals are atmospherically important species, playing a direct role in the HO and NO cycles that affect troposperic air pollution. Alkoxy radicals that can form a six membered transition state can isomerize into a hydroxyalkyl radical. In the presence of O$2$, a rapid association reaction occurs, forming a hydroxyalkylperoxy radical. The \textit{n}-butoxy radical is the smallest alkoxy to undergo isomerization, forming the $\gamma$-hydroxybutylperoxy radical (HOC$4$H$8$OO). Direct detection of HOC$4$H$8$OO opens the door to measuring alkoxy reaction kinetics with higher precision than previous end product studies. \textbf{2006}, \textit{6}, 3625.} In this talk, we report the first detection of the ~{A}-~{X} electronic spectrum of the HOC$4$H$8$OO radical. The spectrum is similar in shape to the ~{A}-~{X} spectrum of \textit{n}-butyl peroxy: \textbf{2005}, \textit{109}, 11191.} a broad spectroscopic band due to the multiple molecular conformers that are present. We also use the ~{A}-~{X} band to measure the alkoxy isomerization kinetics relative to the alkoxy radical's reaction with O$2$, similar to the previous kinetics studies.