Using ab initio unrestricted Hartree−Fock, restricted open-shell Hartree−Fock, and fourth-order perturbation theory methods, 13 minima on the Si2CH4+ potential energy surface have been calculated including ion−molecule complexes, Si−H and C−H insertion products, and other Si2CH4+ isomers. The transition states connecting those isomers have been located and the minimum energy paths have been tra...

In this paper, the free vibration analysis of sandwich micro beam with piezoelectric layers based on the modified couple stress and surface elasticity theories are investigated. The Hamilton’s principle is employed to derive the sandwich micro beam with piezoelectric based on modified couple stress theory incorporating with Gurtin- Murdoch surface theory. The generalized differential quadrature...

I examine the effect of trying to impose a Dirichlet boundary condition on a scalar field by coupling it to a static background. The zero point – or Casimir – energy of the field diverges in the limit that the background forces the field to vanish. This divergence cannot be absorbed into a renormalization of the parameters of the theory. As a result, the Casimir energy of a surface on which a D...

Classical transition state theory ~TST! provides the rigorous basis for the application of molecular dynamics ~MD! to infrequent events, i.e., reactions that are slow due to a high energy barrier. The TST rate is simply the equilibrium flux through a surface that divides reactants from products. In order to apply MD to infrequent events, corrections to the TST rate that account for recrossings ...

Theoretical calculations of thermal spin transitions in nanoscale clusters on a surface are presented. The mechanisms for magnetization reversal are identified and the activation energy and pre-exponential factor for the rate are evaluated using a recently developed harmonic transition state theory and a Heisenberg-type Hamiltonian. A maximum is found in the pre-exponential factor as a function...

Submesoscale (1–200km) wavenumber spectra of kinetic and potential energy and tracer variance are obtained from in situ observations in theGulf Stream region and in the eastern subtropical North Pacific. In the Gulf Stream region, steep kinetic energy spectra at scales between 200 and 20km are consistent with predictions of interior quasigeostrophic–turbulence theory, both in the mixed layer an...

0022-3115/$ see front matter Published by Elsevier doi:10.1016/j.jnucmat.2008.12.318 * Corresponding author. Tel.: +1 310 794 5990; fax E-mail address: [email protected] (S. Sharafat). Bubble growth and gas release during annealing of helium implanted tungsten is described using a Kinetic Monte Carlo approach. Implantation of tungsten with low energy He ions results in the unusual formation of ...

The electronic properties of colloidal quantum dots (QDs) are critically dependent on both QD size and surface chemistry. Modification of quantum confinement provides control of the QD bandgap, while ligand-induced surface dipoles present a hitherto underutilized means of control over the absolute energy levels of QDs within electronic devices. Here, we show that the energy levels of lead sulfi...

A relatively simple treatment using perturbation theory is proposed to describe spectrum of pseudorotational states in cyclic-N(3). The purpose is to develop an analytical expression that could be used to fit the experimentally determined spectrum of cyclic-N(3), with purpose of identifying this molecule in the laboratory and deriving parameters of its potential energy surface directly from the...