A comparative study of large magnetic field effect on the radical pair generated by the photo-induced electron transfer from indoles to 2,4,6-triphenyl pyrylium tetrafluoroborate and its thia-analogue
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- 作者：Halder ; Mintu
- 关键词：Magnetic field effect ; Photo-induced electron transfer ; Micelle ; Interface
- 刊名：Chemical Physics
- 出版年：2004
- 出版时间：August 23, 2004
- 年：2004
- 卷：303
- 期：3
- 页码：243-253
- 全文大小：432 K
文摘
The effect of external magnetic field on the spin evolution of the radical pair (RP) generated by photo-induced electron transfer from indoles to 2,4,6-triphenyl pyrylium tetrafluoroborate and its thia-anologue for ring-sulfur in aqueous SDS micellar medium has been investigated. The transient signal observed at 555 nm at low fields was found to consist of a fast rise followed by decay; at high fields, an additional slow growth at the intermediate time delay was observed. The observed decay was explained in terms of a kinetic scheme involving multiple channels for radical formation. The yield of escape radicals increases gradually with increase of the field and ultimately reaches saturation. At low fields the magnetic field dependence of the escape yield is ascribed to competition between HFI and Zeeman effect and at higher fields, to the relaxation mechanism induced by anisotropic HFI [δ(hfi)]. Saturation in MFE is observed at high fields which is a consequence of the competition between the spin-re-phasing process and the fast escape process.