Journal of Physical Chemistry A p. 10 - 20 (1999)
Update date:2022-08-11
Topics:
Yip
Levy, Donald H.
Kobetic, Renata
Piotrowiak, Piotr
The dependence of the rate of singlet excitation transfer on the donor-acceptor energy gap was investigated in bichromophoric spiranes with symmetry-forbidden zero-order electronic coupling. The fluorescence measurements were performed in a supersonic jet in order to avoid collisional and inhomogeneous line broadening. Fluorescence excitation spectra and single-vibronic-level emission spectra of the model chromophores cyclopentaphenanthrene and 1,8-dimethylnaphthalene and the bichromophores spirofluorenephenanthrene and spirofluorenenaphthalene are presented and analyzed. Although the transition moments of the linked chromophores are rigorously perpendicular and the exchange coupling between the v′ = 0 states is computationally shown to be zero, all spiranes with energy gaps larger than ~1000 cm-1 exhibited complete electronic energy transfer from all vibrational states of the electronically excited donor, including the undistorted v′ = 0 state. This behavior is explained in terms of vibronic coupling between the sparse states of the donor and the dense manifold (pseudocontinuum) of the acceptor states. The electronic energy transfer was sufficiently fast to result in measurable lifetime broadening of the donor absorption lines, from which the kEET was estimated. The results demonstrate that the zero-order picture overestimates the degree of the molecular orbital symmetry control over electronic energy transfer and charge-transfer rates and that at sufficiently high driving forces the vibronically mediated "symmetry-forbidden" electronic energy transfer can be very rapid (~1 × 1012 s-1).
View MoreContact:0833-5590788/5590338/5590055
Address:Victory in the town of Red Star Village,Mount Emei City,industrial concentration area storage processing logistics parkpark
Shanghai PuYi Chem-Tech Co.,Ltd.
Contact:+86-21-57687505-227
Address:3 Floor, Building 11, No 201 MinYi Road, Songjiang District, Shanghai 201612, China
Contact:+86-717-6370352
Address:168 Chengdong Avenue, Yichang, Hubei 443003, P. R.China
Anyang Double Circle Auxiliary CO.,LTD
Contact:0086-134 6082 4403
Address:dongfeng road, anyang city, henan province,china
Jiangsu Cale New Material Co.ltd
Contact:+86-515-88334667/88203550
Address:Zhongshan 3rd Road, Coastal Chemical Industry Park, Yancheng, Jiangsu, China
Doi:10.1039/c4ra07012g
(2014)Doi:10.1007/BF00913835
(1952)Doi:10.1021/ja01002a023
(1967)Doi:10.1016/S0040-4039(00)79277-X
(1993)Doi:10.1021/jo01363a018
(1957)Doi:10.1016/j.ejmech.2017.06.067
(2017)