Charge transfer due to collisions of ground-state O3+(2s22p P2) ions with He is investigated using the quantum-mechanical molecular-orbital close-coupling (QMOCC) method. The ab initio adiabatic potentials and radial ...
详细信息
Charge transfer due to collisions of ground-state O3+(2s22p P2) ions with He is investigated using the quantum-mechanical molecular-orbital close-coupling (QMOCC) method. The ab initio adiabatic potentials and radial couplings utilized in the QMOCC calculations are obtained from the multireference single- and double-excitation configuration interaction approach. State-selective and total charge-transfer cross sections are calculated for collision energies from 0.01 eV/u to 1 keV/u. Comparison with existing data reveals that the present QMOCC calculations are in good harmony with the measured total single-electron charge-transfer cross sections. Excellent agreement with the available experimental data is also found for state-selective cross sections at the measured energy region.
The electron and hole states and confining potential for cylindrical core-shell structure with type-II band alignment are obtained from a numerical solution of the self-consistent Schrödinger-Poisson system of eq...
详细信息
The electron and hole states and confining potential for cylindrical core-shell structure with type-II band alignment are obtained from a numerical solution of the self-consistent Schrödinger-Poisson system of equations. The photoluminescence (PL) kinetics is theoretically analyzed, with the nanostructure size dispersion taken into account. The results are applied to the radiative recombination in the system of ZnTe/ZnSe stacked quantum dots. A good agreement with both cw and time-resolved experimental observations is found. It is shown that size distribution results in the PL decay that has essentially nonexponential behavior even at the tail of the decay where the carrier lifetime is almost the same due to slowly changing overlap of the electron and hole wave functions. Finally, a model situation applicable to colloidal core-shell nanowires is investigated and discussed.
We investigate the dissociation of O2 on Pb(111) surface using first-principles calculations. It is found that in a practical high-vacuum environment, the adsorption of molecular O2 takes place on clean Pb surfaces on...
We investigate the dissociation of O2 on Pb(111) surface using first-principles calculations. It is found that in a practical high-vacuum environment, the adsorption of molecular O2 takes place on clean Pb surfaces only at low temperatures such as 100 K, but the O2 easily desorbs at (elevated) room temperatures. It is further found that the Pb adatoms enhance the molecular adsorption and activate the adsorbed O2 to dissociate during subsequent room-temperature annealing. Our theory explains the observation of a two-step oxidation process on the Pb surfaces by the unique role of Pb adatoms.
In recent years, a series of opacity diagnostics have been developed at the Research Center of Laser Fusion in China. Two types of cavities (a conical cavity called a type I target, and a cylindrical cavity with foam ...
This paper investigates the interaction of a small number of modes in the two-fluid Kelvin-Helmholtz instability at the nonlinear regime by using a two-dimensional hydrodynamic code. This interaction is found to be re...
详细信息
This paper investigates the interaction of a small number of modes in the two-fluid Kelvin-Helmholtz instability at the nonlinear regime by using a two-dimensional hydrodynamic code. This interaction is found to be relatively long range in wave-number space and also it acts in both directions, i.e. short wavelengths affect long wavelengths and vice versa. There is no simple equivalent transformation from a band of similar modes to one mode representing their effective amplitude. Three distinct stages of interaction have been identified.
We introduce the problem of communication with partial information, where there is an asymmetry between the transmitter and the receiver codebooks. Practical applications of the proposed setup include the robust signa...
详细信息
We introduce the problem of communication with partial information, where there is an asymmetry between the transmitter and the receiver codebooks. Practical applications of the proposed setup include the robust signal hashing problem within the context of multimedia security and asymmetric communications with resource-lacking receivers. We study this setup in a binary detection theoretic context for the additive colored Gaussian noise channel. In our proposed setup, the partial information available at the detector consists of dimensionality-reduced versions of the transmitter codewords, where the dimensionality reduction is achieved via a linear transform. We first derive the corresponding MAP-optimal detection rule and the corresponding conditional probability of error (conditioned on the partial information the detector possesses). Then, we constructively quantify an optimal class of linear transforms, where the cost function is the expected Chernoff bound on the conditional probability of error of the MAP-optimal detector.
We show that classical many-particle systems interacting with certain soft pair interactions in two dimensions exhibit novel low-temperature behaviors. Ground states span from disordered to crystalline. At some densit...
详细信息
We show that classical many-particle systems interacting with certain soft pair interactions in two dimensions exhibit novel low-temperature behaviors. Ground states span from disordered to crystalline. At some densities, a large fraction of normal-mode frequencies vanish. Lattice ground-state configurations have more vanishing frequencies than disordered ground states at the same density and exhibit vanishing shear moduli. For the melting transition from a crystal, the thermal expansion coefficient is negative. These unusual results are attributed to the topography of the energy landscape.
Charge transport in DNA molecules has raised considerable interest because of its importance in biological processes and potential applications in nanoscale devices. A DNA molecule can be viewed as a quasi-one-dimensi...
详细信息
Charge transport in DNA molecules has raised considerable interest because of its importance in biological processes and potential applications in nanoscale devices. A DNA molecule can be viewed as a quasi-one-dimensional system composed of stacked base pairs (AT, CG) together with backbones of sugar phosphates. Motivated by recent experimental observations on the importance of the backbone integrity, we investigate the interplay between charge transport through the ordered backbone and disordered base stacks with random sequences. By analytical and numerical calculations, we find that the coupling between the backbone and base-pair channels plays an important role in charge transport. The backbone can generate effective hopping constants well beyond the adjacent base pairs, enhancing charge transport through the base-pair channel. The corresponding enhancement of the localization length is nearly independent of the length of the DNA and increases with increasing coupling between backbone and base pair. Our model can explain qualitatively several experimental observations.
Dense hard-particle packings are intimately related to the structure of low-temperature phases of matter and are useful models of heterogeneous materials and granular media. Most studies of the densest packings in thr...
详细信息
Dense hard-particle packings are intimately related to the structure of low-temperature phases of matter and are useful models of heterogeneous materials and granular media. Most studies of the densest packings in three dimensions have considered spherical shapes, and it is only more recently that nonspherical shapes (e.g., ellipsoids) have been investigated. Superballs (whose shapes are defined by |x1|2p+|x2|2p+|x3|2p≤1) provide a versatile family of convex particles (p≥0.5) with both cubic-like and octahedral-like shapes as well as concave particles (0
暂无评论