| Abstract
| - The transition between single step long-range tunneling and multistep hopping transport in DNA electrontransfer depends on a myriad of factors including sequence, distance, conformation, solvation and, consequently,hole state energetics. We show that the solvation energetics of hole (radical cation) states in DNA is comparableto the quantum delocalization energetics of the hole. That is, the solvation forces that tend to localize thehole compete with the quantum effects that give rise to hole delocalization. The net result is that the holestates are predicted to be relatively compact (one to three base pairs in length) and that the “trap depth” ofthese holes is expected to be much shallower than anticipated by gas-phase quantum chemical analysis ofbase stacks. This analysis predicts guanine oxidation potential dependence on the length of GC runs to bemodest (differences <0.1 V for holes from one to three base pairs). The lowering of the trapped hole bindingenergy has significant implications for the structure and mobility of hole states in DNA.
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