Resonance tunneling

As this first example indicates, experiments involving superlattices have an additional complication compared to the ADQW treated previously. In the ADQW, essentially all quantities of interest can be calculated analytically. The well widths and barriers widths are designed such that the electronic levels move into tunneling resonance at a value of the DC field sufficient to immobilize the holes. This is not guaranteed to be the case in superlattices, where the electronic levels display a complicated pattern of repulsion and anticrossing as the DC field is varied. In addition, as shown... 

Chi Q, Farver O, Ulstrup J (2005) Long-range protein electron transfer observed at the singlemolecule level in situ mapping of redox-gated tunneling resonance. Proc Natl Acad Sci USA 102 16203-16208... 

Mazur U, Hipps KW (1994) Unoccupied orbital mediated tunneling resonance-like structures in the tunneling spectra of polyacenes. J Phys Chem 98 5824—5829... 

In Sec. 2, we make use of the detailed balance conditions for derivation of a generic expression for the mean charge of the quantum dot. We formulate the field effect on the splitting and broadening of the tunnel resonance for adiabatic... 

Field, R.W. Jonas, D.M. Kinsey, J.L. Chen, Y.Q. Acetylene to vinylidene isomerization — tunneling resonances in eigenstate resolved spectra. In Abstracts of papers of the American Chemical Society 199, 156-PHYS Part 2, Apr 22, 1990. 

One has at hand, therefore, a completely general semiclassical mechanics which allows one to construct the classical-limit approximation to any quantum mechanical quantity, incorporating the complete classical dynamics with the quantum principle of superposition. As has been emphasized, and illustrated by a number of examples in this review, all quantum effects— interference, tunnelling, resonances, selection rules, diffraction laws, even quantization itself—arise from the superposition of probability amplitudes and are thus contained at least qualitatively within the semiclassical description. The semiclassical picture thus affords a broad understanding and clear insight into the nature of quantum effects in molecular dynamics. 

F. Delgado, J.G. Muga, A. Ruschhaupt, Preparation of ultralow atomic velocities by transforming bound states into tunneling resonances, Phys. Rev. A 74 (2006) 063618. 

Using these two methods nanoscale circuits, consisting of conductors, semiconductors and isolating areas, can be obtained. Elements such as tunnel resonant diodes and single electron transistors can be the structural elements of such circuits, analogous to devices described in the literature [50]. 

This estimate shows that flie widths of two adjacent tunneling resonances are significantly smaller than their spacing, hu>. Such resonances are said to be non-overlapping. 

We already encountered such behavior in Section 4.3.6, where the rate of decay of tunneling resonances is much smaller than the rate of approach to the barrier that coniines these states. 

It is quite straightforward to perform quasiclassical trajectory computations (QCT) on the reactions of polyatomic molecules providing a smooth global potential energy surface is available from which derivatives can be obtained with respect to the atomic coordinates. This method is described in detail in Classical Trajectory Simulations Final Conditions. Hamilton s equations are solved to follow the motion of the individual atoms as a function of time and the reactant and product vibrational and rotational states can be set or boxed to quantum mechanical energies. The method does not treat purely quantum mechanical effects such as tunneling, resonances. or interference but it can treat the full state-to-state, eneigy-resolved dynamics of a reaction and also produces rate constants. Numerous applications to polyatomic reactions have been reported. ... 

---