摘要
按照CI的酉群方法,以Gelfand基构造多电子波函数,采用四轨道模型,进行了对位及间位硝基苯基甲基多硅烷体系的EHMO-CI计算,得到的第1、第2及第3跃迁能与实验值接近。对位硝基苯基甲基多硅烷体系的第1吸收带随硅原子数增加(或支化)呈现的红移现象是LUMO中硅的d轨道以π_d(si)的形式与苯环π~*(ph)共轭作用的变化及d轨道成分与硝基成分变化引起的CI中电子排斥作用变化所致,其跃迁机理是以苯环为主的π→π~*跃迁。
The UV spectra of p-NO2-m-(SiMem- 3)n (SiMe3)n and m-NO2-ph (SiMem-3) (SiMe3)m systems (m= 1, n = 0,1,2; m = 2n= 1) are analyzed by means of the EHMO-CI-SPIN-FREE method with four orbital model. The first, second and third absorpt on bands arise in essence from π→π * transitions. Furthermore, the d atomic orbital of silicon chain may play an important role in the red shift of first absorption bands of p-NO2-ph(SiMe3-m), (SiMe3)m system. This can be considered due to two effects. One of them is the conjugation of d orbital (πd(Si)) with π*(ph) in LUMO. The other is the changing of electronic repulsion by changing d orbital and NO2 group components in LUMO.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
1989年第1期72-76,共5页
Chemical Journal of Chinese Universities
基金
国家自然科学基金
关键词
UV谱
硅烷
EHMO-Cl
Nitrophenylpo lysilanes, EHMO-Cl, d-Orbital (Si)
