Origin of substituent effects in the absorption spectra of peroxy radicals: Time dependent density functional theory calculations

被引:46
作者
Weisman, JL
Head-Gordon, M [1 ]
机构
[1] Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA
[2] Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA
关键词
D O I
10.1021/ja011368e
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
We investigate the assignment of electronic transitions in alkyl peroxy radicals. Past experimental work has shown that the phenyl peroxy radical exhibits a transition in the visible region; however. previous high level calculations have not reproduced this observed absorption. We use time dependent density functional theory (TDDFT) to characterize the electronic excitations of the phenyl peroxy radical as well as other hydrocarbon substituted peroxy radicals. TDDFT calculations of the phenyl peroxy radical support an excitation in the visible spectrum. Further, we investigate the nature of this visible absorption using electron attachment/detachment density diagrams of the peroxy radicals and present a qualitative picture of the origin of the visible absorption based on molecular orbital perturbations. The peroxy radical substituent is also compared against isoelectronic radical groups. The visible absorption is determined to be dependent on mixing of the alkyl and radical substituent orbitals.
引用
收藏
页码:11686 / 11694
页数:9
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