Discrete distribution of implanted and annealed arsenic atoms in silicon nanowires and its effect on device performance.

We have theoretically investigated the effects of random discrete distribution of implanted and annealed arsenic (As) atoms on device characteristics of silicon nanowire (Si NW) transistors. Kinetic Monte Carlo simulation is used for generating realistic random distribution of active As atoms in Si NWs. The active As distributions obtained through the kinetic Monte Carlo simulation are introduced into the source and drain extensions of n-type gate-all-around NW transistors.

Dopant-induced intrinsic bistability in a biased nanowire.

Self-consistent calculations of quantum transport through a single donor atom in the semiconductor nanowire show intrinsic bistability of the nonequilibrium electronic state. We attribute this effect to two distinct ion screening mechanisms.

Tunneling splitting and decay of metastable states in polyatomic molecules: invariant instanton theory.

This paper gives an overview of recently developed instanton theory of multidimensional tunneling and demonstrates its applicability to real polyatomic systems. One of the key features of the present formulation is rigorous solution of the multidimensional Hamilton-Jacoby and transport equations which constitutes the basis of the semiclassical theory accurate up to the first order in the Planck constant variant Planck's over 2pi. Apart from this fundamental assumption of the semiclassical dynamics the present instanton theory is exact, i.

Collision energy dependence of the O(1D) + HCl --> OH + Cl(2P) reaction studied by crossed beam scattering and quasiclassical trajectory calculations on ab initio potential energy surfaces.

The dynamics of the O(1D) + HCl --> OH + Cl(2P) reaction are investigated by a crossed molecular beam ion-imaging method and quasiclassical trajectory calculations on the three ab initio potential energy surfaces, the ground 1(1)A' and two excited (1(1)A'' and 2(1)A') states. The scattering experiment was carried out at collision energies of 4.2, 4.

Generalized trajectory surface hopping method based on the Zhu-Nakamura theory.

We present a generalized formulation of the trajectory surface hopping method applicable to a general multidimensional system. The method is based on the Zhu-Nakamura theory of a nonadiabatic transition and therefore includes the treatment of classically forbidden hops. The method uses a generalized recipe for the conservation of angular momentum after forbidden hops and an approximation for determining a nonadiabatic transition direction which is crucial when the coupling vector is unavailable.

Tunneling splitting of energy levels and rotational constants in the vinyl radical C2H3.

The instanton theory newly implemented by two of the authors (G.V.M.

Incorporation of nonadiabatic transition into wave-packet dynamics.

Nonadiabatic wave-packet dynamics is factorized into purely adiabatic propagation and instantaneous localized nonadiabatic transition. A general formula is derived for the quantum-mechanical local nonadiabatic operator which is implemented within the framework of the R-matrix method. The operator can be used for incorporating the nonadiabatic transition in semiclassical wave-packet dynamics.

Instanton theory for the tunneling splitting of low vibrationally excited states.

We develop the instanton theory for calculating the tunneling splitting of excited states. For the case of low vibrational quantum states we derive a canonically invariant formula which is applicable to a multidimensional system of arbitrary Riemannian metric. The effect of multidimensionality in relation to the vibrational excitation is explained in terms of the effective frequencies along the instanton trajectory.

Laser control of electronic transitions of wave packet by using quadratically chirped pulses.

An effective scheme is proposed for the laser control of wave packet dynamics. It is demonstrated that by using specially designed quadratically chirped pulses, fast and nearly complete excitation of wave packet can be achieved without significant distortion of its shape. The parameters of the laser pulse can be estimated analytically from the Zhu-Nakamura theory of nonadiabatic transition.

Evaluation of canonical and microcanonical nonadiabatic reaction rate constants by using the Zhu-Nakamura formulas.

We consider a problem of calculating both thermal and microcanonical rate constants for nonadiabatic chemical reactions. Instead of using the conventional transition state theory, we use a generalized seam surface and introduce a concept of a coordinate dependent effective nonadiabatic transition probability based on the Zhu-Nakamura theory which can treat the nonadiabatic tunneling properly. The present approach can be combined with Monte Carlo method so as to be applicable to chemical reactions in complicated systems.

Simple and accurate method to evaluate tunneling splitting in polyatomic molecules.

A practical and accurate semiclassical method for calculating the tunneling splitting of the ground state in polyatomic molecules is presented based on a recent version of the instanton theory [J. Chem. Phys.