Band Structure Calculation of Si and Ge by Non-Local Empirical Pseudo-Potential Technique

In this paper, the principle of spatial nonlocal empirical pseudopotential and its detailed calculation procedure is presented. Consequently, this technique is employed to calculate the band structures of Silicon and Germaniun. By comparing the results with photoemission experimental data, the validity and accuracy of this calculation are fully conformed for valence or conductance band, respectively. Thus it can be concluded that the spin-orbit Hamiltonian will only affect the energy band gap and another conductance or valence band structure. Therefore, this nonlocal approach without spin-orbit part is adequate for the device simulation of only one carrier transport such as metal oxide semiconductor field effect transistors (MOSFET)’s, and it can significantly reduce the complication of band structure calculation.

A First-principles Calculation of Structures and Stability of Al_(13)I Cluster

Using first-principles pseudo-potential plane wave method, the energetics, geometrical and electronic structures of three Al13I cluster isomers were calculated. The calculation results of the binding energy indicate Al13I cluster is more stable than Al13 cluster although its electrons are not a magic number as in Alia cluster, and among Al13I cluster isomers the ＂Bridge＂ structure is the most stable, the second is the ＂Ontop＂ structure, and the worst is the ＂Hollow＂ structure. By analyzing the geometrical structures of Al13I cluster isomers, it is found that after I atom and Al13 cluster combine the geometrical structures of Al13 moieties are changed besides Al13I Hollow cluster, in which the Alia moiety is still a regular icosahedron. For Al13I Ontop cluster, the Al13 moiety has a shrinking trend to I, whereas in Al13I Bridge cluster it is distorted. Mulliken population analysis shows for the interaction of electrons between Al-I atoms in Al13I cluster not only there exists an ionic bonding but there is a covalent bonding. Part of electrons in the Alia cluster transfer to I as Al13 cluster and I atom combine. The order of the strength of covalent bonding between Al13 moiety and I in Al13I cluster isomers is Al13IBridge〉Al13IHollow〉Al13I Ontop. Further analysis of electric structures of Al13 and Al13I clusters indicates a higher stability of Al13I cluster than Al13 cluster can be attributed to the s-p hybridization of 3s and 3p electrons of Al in Al13 moiety induced by 1 doped, which leads to fewer electrons N（EF） at EF in Al13I and a larger energy gap △EH-L between HOMO and LUMO levels in Al13I cluster. The distinguish of structural stability of Al13I cluster isomers mainly originates from their different magnitudes .in decrease of N（EF） and increase of △EH-L relative to Al13 cluster. The fewest N（EF） and the largest △EH-L are responsible for the high stability of Al13I Bridge cluster.

Propagation of Electrostatic Waves in an Ultra-Relativistic Dense Dusty Electron-Positron-Ion Plasma

The nonlinear propagation of waves (specially solitary waves) in an ultra-relativistic degenerate dense plasma (containing ultra-relativistic degenerate electrons and positrons, cold, mobile, inertial ions, and negatively charged static dust) have been investigated by the reductive perturbation method. The linear dispersion relation and Korteweg de-Vries equation have been derived whose numerical solutions have been analyzed to identify the basic features of electrostatic solitary structures that may form in such a degenerate dense plasma. The existence of solitary structures has been also verified by employing the pseudo-potential method. The implications of our results in astrophysical compact objects have been briefly discussed.

QUASI-VARIATIONAL PRINCIPLE FOR THE VORTEX-POTENTIAL FUNCTION OF ROTATIONAL FLOW IN THREE-DIMENSION PIPE

The variational analysis of the Pseudo-potential function-vortex-potential function model, a new mathematical model, was developed and by which the flow field with transonic speed and curl was decided, and different sorts of the variational principle for vortex potential function were established by transforming the original equation for vortex-function, the boundary conditions for vortex-potential function was raised.

Simulation of two-phase flows of a droplet impacting on a liquid film with an improved lattice Boltzmann model

Based on the lattice Boltzmann method（LBM）,an improved pseudo-potential model,combined with a method of adding force term,is used to simulate the two-phase flows caused by a liquid droplet impacting on a liquid film.In this model,the different phases are treated as one fluid,and the interfaces between the vapor and liquid phases can be obtained by density value of the fluid.This variant of the LBM allows one to obtain the densities of vapor and liquid with high accuracy.The model is validated by an example of phase separation.The early stage of the impact of droplet on liquid film is simulated,and the results are qualitatively consistent with physical phenomena.

Molecular Structure, Electronic Structure, Properties and Analyses of Five Azopyridine Ruthenium Complexes α-Cl, β-Cl, γ-Cl, δ-Cl and ε-Cl of RuCl₂(4,6-Dimethyl-Phenylazopyridine)₂as Potential Cancer Drugs: DFT and TD-DFT Investigations

Ground state geometries, natural bond orbital (NBO), analysis of frontier molecular orbitals (FMOs), analysis and spectral (RMN and UV-Visible) properties of five azopyridine ruthenium (II) complexes α-Cl, β-Cl, γ-Cl, δ-Cl and ε-Cl of RuCl2(Dazpy)2 have been theoretically studied by the Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) methods using two basis sets: Lanl2DZ and a generic basis set in gas or in chloroform solvent. Dazpy stands for 4,6-dimethyl-phenylazopyridine. Optimized geometry shows that, except β-Cl, all the other four isomers α-Cl, γ-Cl, δ-Cl and ε-Cl are C2 symmetrical. Otherwise, a good agreement was found between experimental and the calculated geometry and NMR data. Moreover, Lanl2DZ effective core potential basis set provides good chemical shifts and geometric properties. Furthermore, the prediction of the frontier orbitals (Highest Occupied Molecular Orbital or HOMO and Lowest Unoc-cupied Molecular Orbital or LUMO) shows that the most active isomer suita-ble for electronic reactions is admitted to be δ-Cl. Besides, the NBO analysis indicates that the Ru-N is formed by the electron delocalization of lone pair atomic orbital of N2 and Npy to Ru. Also, the strongest interactions between LP(N) with LP*(Ru) and LP(Cl) with LP*(Ru) stabilize the molecular struc-ture. In addition, NBO shows that the five d orbitals of Ru in the complex are organized so that there is no order of priority from one complex to another. Therefore, the transition LP(Ru) → π*(N1 = N2) corresponding to Metal to Li-gand Charge Transfer (MLCT) is in reality no more than d → π*. Besides, TDDFT prediction in chloroform solvent reveals that all the five isomerics complexes absorb in the visible region as well as efficient photosensitizers. What’s more, δ-RuCl2(dazpy)2 can potentially act as the excellent sensitizer with a large band of absorption in visible region and a small excited energy. This study can help design and find out the ability or properties of the com-plex to behave as sensitizer or potential cancer drugs.

Cooperative engineering the multiple radio-frequency fields to reduce the X-junction barrier for ion trap chips

With the increasing number of ion qubits and improving performance of sophisticated quantum algorithms,more and more scalable complex ion trap electrodes have been developed and integrated.Nonlinear ion shuttling operations at the junction are more frequently used,such as in the areas of separation,merging,and exchanging.Several studies have been conducted to optimize the geometries of the radio-frequency(RF)electrodes to generate ideal trapping electric fields with a lower junction barrier and an even ion height of the RF saddle points.However,this iteration is time-consuming and commonly accompanied by complicated and sharp electrode geometry.Therefore,high-accuracy fabrication process and high electric breakdown voltage are essential.In the current work,an effective method was proposed to reduce the junction’s pseudo-potential barrier and ion height variation by setting several individual RF electrodes and adjusting each RF voltage amplitude without changing the geometry of the electrode structure.The simulation results show that this method shows the same effect on engineering the trapping potential and reducing the potential barrier,but requires fewer parameters and optimization time.By combining this method with the geometrical shapeoptimizing,the pseudo-potential barrier and the ion height variation near the junction can be further reduced.In addition,the geometry of the electrodes can be simplified to relax the fabrication precision and keep the ability to engineer the trapping electric field in real-time even after the fabrication of the electrodes,which provides a potential all-electric degree of freedom for the design and control of the two-dimensional ion crystals and investigation of their phase transition.

THE NONLINEAR ROSSBY WAVES IN A BAROCLINIC ATMOSPHERE

Under semi-geostrophic approximation, the governing equations of motion for a three-dimensional baroclinic atmosphere can be written

Electronic structure of(InSb)_m/(HgTe)_n short period superlattices

Theelectronicstructureof（InSb）m/（HgTe）nshortperiodsuperlatticesgrownalongthe（001）directionis studiedtheoreticallyusingnorm-conservingpseudo-potentialstogetherwiththelocal-densityapproximationforthe exchange-correlationpotential.Thebandstructuredependsonthevalueofmandn,thenumberofmono-layersand on the ordering of atoms at the InSb/HgTe interface in one unit cell. Our calculation indicates that the superlattice can be a semiconductor having a band gap between the occupied and unoccupied bands, or a metal with no band gap at the Fermi energy. According to the further calculation of total charge density between（InSb）m/（HgTe）nwith different structures, a clearly different behavior happens when the structure changes from a system with a gap and a system without a gap.