Tight binding model bridge

Current transfer shifts both charge and momentum from donor to acceptor. We have reviewed time-dependent [38] and steady-state [39, 40] descriptions of current transfer through chiral bridges [36, 37]. In the tight-binding models, current transfer arises from coherent interferences between resonant or tunneling paths. This kind of interference has received attention in recent studies of molecular wires and nanodots [45-50]. 

The actual way by which an imposed potential bias distributes itself on the molecular bridge depends on the molecular response to this bias, and constitutes part of the electronic structure problem. Starting from the imbiased junction in Fig. 17.6(a) (shown in the local representation of a tight binding model similar to... 

A standard model for ET in donor (D)-bridge (B)-acceptor (A) systems describes the donor, bridge, and acceptor species as tight-binding chains [2-9]. The corresponding Hamiltonian is H Hr, I II, I // I V/sa + Vbd- where... 

The model is based on the standard tight-binding Hamiltonian consisting of a donor, a number of bridge sites, and an acceptor, all coupled to form a linear chain. In addition, a single linearly coupled oscillator is included, representing a high-frequency vibrational coordinate coupled to the electron transfer. The lack of detailed information about this system makes it appropriate to treat the bath stochastically. Thus... 

Figure 14.12 The swinging cross-bridge model of muscle contraction driven by ATP hydrolysis, (a) A myosin cross-bridge (green) binds tightly in a 45 conformation to actin (red), (b) The myosin cross-bridge is released from the actin and undergoes a conformational change to a 90 conformation (c), which then rebinds to actin (d). The myosin cross-bridge then reverts back to its 45° conformation (a), causing the actin and myosin filaments to slide past each other. This whole cycle is then repeated.

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