Figure 5.

The qualitative tunneling energy dependence of β according to Eqs. 4 and 5 in DNA hairpins (solid line) and all-trans alkanes (dashed line). Maximum values of β are estimates based on experimental data. Vertical lines represent the negative IPs for alkanes and T:A base pairs. The boxes represent the range of tunneling energies for the DNA hairpins in the present study, in which the tunneling energies are nearly as large in magnitude as the base-pair IPs, and for studies of ET in systems with alkane bridges, in which the tunneling energies are much smaller in magnitude than the alkane IPs.