Effect Of Interaction Potential Research Articles

Thermodynamic properties of two electrons quantum dot with harmonic interaction

We present a theoretical study of the effect of the Harmonic e–e interaction on the thermodynamic properties of one dimensional parabolic quantum dot. The energy spectrum for two electrons is obtained by solving the Schrödinger wave-equation analytically. These energy levels are employed to calculate the mean energy, heat capacity Helmholtz free energy and entropy of the quantum dot system using canonical ensemble approach. It is noted that for small values of temperature the mean energy increases slowly with temperature, but with further increase in temperature the mean energy becomes independent of interaction strength and it increases more rapidly. However the mean energy increasing monotonically with increasing confinement strength and this increase becomes linear in the weak confinement region. As a function of electro’s separation it is found that initially the mean energy decreases with increasing the separation and the effect of temperature change is negligible but after a certain distance beyond which the effect of the change in temperature is noticeable on the mean energy and it displays an asymptotic behavior. As a function of confinement length. The mean energy is found to decrease with increasing confinement strength, but with further increase in confinement length the confinement effect on the mean energy becomes intangible when the dot size lo is as larger than 12 nm. It is observed that for small values of temperature heat capacity increases very rapidly and then tends to saturate with a value of 2kB as temperature increases. It is also shown that the effect of interaction strength on both heat capacity and mean energy is tangible at low temperature like T=10K an 20 K, and the effect becomes negligible at sufficiently high temperature values like T=30 and 40 K. The variation of entropy with interaction strength shows interesting behavior, it is noted that, in the low interaction strength region, entropy remains constant with interaction strength, while it begins to increase rapidly as the interaction strength increases where the effect of interaction potential becomes more and more pronounced. Also, to ensure the stability and confinement of the QD system F-T curves are drawn. It is shown that the greater the strength of interaction, the more stable the system will be. It is also shown that our approach has limitations in the applicability regarding to the quantum number Nmax and the separation of electrons inside a QD.

Effect of Interaction Potential on Laser-assisted e-Ar Scattering

The interaction potentials between electron and atom play an important role in electron-atom scattering. Using three potential models, the absolute differential cross section has been calculated by the second Born approximation theory. Results show that these model potentials are successful in the laser-assisted e-Ar scattering system. The influence of static potential, exchange potential and polarization potential on the absolute differential cross section is also analyzed and discussed.

Binary collision lattice simulation study of model parameters in monocrystalline sputtering

Cu ejection and sputtering by Ar ions have been studied in the specific case of 5 KeV Ar impinging the (100), (110) and (111) surfaces using the binary collision lattice simulation code COSIPO. The influence of various parameters in treating the binary collisions has been studied. On the basis of these studied the feasibility of binary collision lattice simulations in connection with sputtering is discussed. The effect of interaction potential on sputtering is studied by using two different potential functions for the ion-atom and atom-atom interaction potentials. The strengths of the potentials have been changed by using various screening lengths and cut-offs. To model electronic stopping both frictional and impact parameter dependent electronic losses are used. It is found that the angular distributions of the sputtered atoms depend mainly on the atom-atom interaction potential. The iron-atom potential and the electronic stopping have only minor effects. The yield, however, depends markedly on the inelastic energy losses and the ion-atom potential. The sensitivity of the sputtering yield on the potentials and on the parameters in treating the binary collisions as well as the influence of the simultaneous collisions depend critically on the strength of the potential. Calculations show that the dependence on these factors is weak if the strengths of the potentials are such that the experimental yield are achieved. Several combinations of the interaction potentials and inelastic losses give good agreement with either experimental yields or angular distributions of sputtered particles. However, a combination exists that reproduces all the experimental results.

Theoretical studies of the angular distributions of oxygen atoms ejected from an ion bombarded c(2 × 2) overlayer of oxygen on Ni(001) II. Effect of interaction potential

Abstract A detailed molecular dynamics study has been performed in order to determine the influence of the interaction potential on the angles of ejection of oxygen atoms from an ion bombarded c(2 × 2) oxygen overlayer on Ni(001). The bonding site of the adsorbate appears to be the dominating factor which influences the angles of ejection. Changing the interaction potential affects the angular distribution similarly to varying the height of the adsorbate above the surface.

Theoretical studies of the angular distributions of oxygen atoms ejected from an ion bombarded c(2 × 2) overlayer of oxygen on Ni(001): II. Effect of interaction potential

A detailed molecular dynamics study has been performed in order to determine the influence of the interaction potential on the angles of ejection of oxygen atoms from an ion bombarded c(2 × 2) oxygen overlayer on Ni(001). The bonding site of the adsorbate appears to be the dominating factor which influences the angles of ejection. Changing the interaction potential affects the angular distribution similarly to varying the height of the adsorbate above the surface.