Distance decay tunneling-pathway model

Figure 4 Distance dependence of driving-force-optimized electron tunneling times in Ru-labeled P. aeruginosa azurin. The sohd line is the distance decay predicted by the tunneling-pathway model for ET along an ideal 8-strand ( 8 = 1.0 A ). The dashed line is the best fit to the data fi =. A ) ...

The pathway model makes a number of key predictions, including (a) a substantial role for hydrogen bond mediation of tunnelling, (b) a difference in mediation characteristics as a function of secondary and tertiary stmcture, (c) an intrinsically nonexponential decay of rate witlr distance, and (d) patlrway specific Trot and cold spots for electron transfer. These predictions have been tested extensively. The most systematic and critical tests are provided witlr mtlrenium-modified proteins, where a syntlretic ET active group cair be attached to the protein aird tire rate of ET via a specific medium stmcture cair be probed (figure C3.2.5). 

Figure 22 Scheme of tip-monolayer-substrate showing relevant distances in multiple conduction pathway model chain-to-chain distance dec, natural alkanethiol length dn, effective thickness as a function of tilt 0. Tunneling through chain (blue) has decay coefficienty c and through space (red) has coefficient yffg. 

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