Electron transfer between biphenyl and biphenyl anion radicals: Reorganization energies and electron transfer matrix elements

✍ Scribed by Li, Xiang-Yuan; He, Fu-Cheng

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 181 KB
• Volume: 20
• Category: Article
• ISSN: 0192-8651
• DOI: 10.1002/(sici)1096-987x(19990430)20:6<597::aid-jcc5>3.0.co;2-c

✦ Synopsis

Intermolecular electron transfer ET between the parallel benzene anion radical and neutral benzene is studied at the UHFr4-31G level. It is found Ž y1 . that the diabatic activation energy remains almost invariant 14.2 kJ mol when d, the distance between the two parallel benzene rings, is ) 0.45 nm. The exponential fall-off of the ET matrix element, V , with d is examined. On the r p basis of the calculated results of the ET matrix element for the system of two parallel benzenes, it is concluded that direct calculation of the ET matrix element, based on the two-state model, is more accurate than that based on the Koopmans theorem. Ab initio calculations are performed in the investigation of the ET reaction between biphenyl anion radical and neutral biphenyl. By using Ž . Ž . the Dunning's 9s, 5p r 3s, 2p basis set with polarization functions on all atoms Ž . DZP , the reorganization energy for the gas phase intermolecular ET is shown to be 109.2 kJ mol y1 . Using the UHFrSTO-3G method and direct calculation of the two-state model, V values of 2.055 kJ mol y1 and 0.429 kJ mol y1 are r p obtained for cyclohexylenyl-and decalenyl-mediated ET systems. When we use the Koopmans theorem instead of the direct calculation, these V values are r p shown to be 1.55 kJ mol y1 and 0.326 kJ mol y1 for the two corresponding systems, respectively.