Through a simple, classical, energy conservation analysis, we propose a finite distance reinterpretation of the standard energy fraction definition used for the single differential cross section (SDCS) for the electron-hydrogen $S$ wave ionization process. The energy modification is due to the fact that, at finite distances from the nucleus, the continuum electrons have to overcome the remaining potential energy to be completely free. As a consequence, the flux formula for extracting - at finite distances - SDCS is also modified. Different from the usual observations, the proposed corrections yield finite and well behaved SDCS values also at the asymmetrical situation where one of the continuum electrons carries all the energy while the other has zero energy. Results of calculations performed at various impact energies, for both singlet and triplet symmetry, are presented and compared favorably with benchmark theoretical data. Although we do not know how, we believe that finite distance effects should strongly affect the evaluation of the flux and consequently the SDCS, also in the full electron-hydrogen case.

A detailed quantum chemical study is performed on the mechanism of the $CH_3OCHFO$ radical formed during the photooxidation of $CH_3OCH_2F (HFE-161),$ including the main decomposition and isomerization processes at the G2(MP2)//MPWB1K level of theory. The results clearly point out that the $\beta-C-H$ bond scission is the dominant path involving the lowest energy barrier of 8.16 kcal $mol^{-1}$ calculated at G2(MP2) level of theory. On the basis of the results obtained during the present investigation, the thermal rate constant for the different reaction channels involved during the isomerization and decomposition processes of $CH_3OCHFO$ are evaluated at 298 $K$ and 1 atm using Canonical Transition State Theory. The results are compared with the data available in the literature.

The p53-MDM2 interaction has been an important target of drug design curing cancers. In this work, Molecular dynamics (MD) simulation coupled with molecular mechanics/Poisson Boltzmann surface area method (MM-PBSA) is performed to calculate binding free energy of peptide inhibitor pDI6W to MDM2. The results show that van der Waals energy is the dominant factor of the pDI6W-MDM2 interaction. Cross-correlation matrix calculated suggests that the main motion of the residues in MMDM2 induced by the inhibitor binding is anti-correlation motion. The calculations of residue-residue interactions between pDI6W and MDM2 not only prove that five residues Phe19’, Trp22’, Trp23’, Leu26’ and Thr27’ from pDI6W can produce strong interactions with MDM2, but also show that $CH$-$π,$ $CH$-$CH$ and $π$−$π$ interactions drive the binding of pDI6W in the hydrophobic cleft of MDM2. This study can provide theoretical helps for anti-cancer drug designs.

The ground-state geometries and energies of $Rh_n (n=2$∼$100)$ clusters are investigated by using Gupta potential combined with the molecular dynamics simulated quenching method and the genetic algorithm. Our results show that: As comparing the lowest energy structure obtained from the simulated quenching method which can be regarded as the ground-state structure, almost all these ground-state geometries can be found (except $Rh_{50})$ by using the genetic algorithm for clusters containing 60 or less atoms, but the efficiency of capturing the ground-state geometry decreases obviously with increasing the cluster size. The effective temperature range for obtaining the ground-state energy (geometry) is obtained by systematically analyzing the energy distributions of the simulated quenching structures, and the correlation between the quenching method of finding the ground-state and the cluster size is also investigated further.

The transmission of femtosecond laser pulses in the Ar atomic-clusters is studied, and the absorption of the laser energy is calculated using a new theoretical model. Then the relevant physics parameters including the continuous winded range, the maximum penetration depth and the stopping time, have been calculated. Thus, we re-examine theoretically the possibility of this model.

We theoretically study high-order harmonic and isolated attosecond pulse generation from a model helion ion in the combination of the mid-infrared (mid-IR) laser and an extreme ultraviolet (xuv) pulse. It is shown that, for the low laser intensity, the harmonic cutoff is at about 657th order, and the supercontinuum with a 287-eV bandwidth is formed. For the high laser intensity, the spectral cutoff is enlarged to 1795th order, and the supercontinuum is broadened to 834 eV. In the two cases, both the long quantum path selection and the enhancement of the supercontinuum are achieved. Especially for the relatively high laser intensity, pure isolated sub-50 as pulses can be directly obtained by superposing an arbitrary 87-eV harmonics in the supercontinuum from 450th to 1590th order.

A scheme is proposed for implementing a two-qubit quantum logic gate and realizing the Deutsch-Jozsa algorithm in cavity QED. In the scheme a three-level atom interacts with highly detuned cavity modes. The gate is not affected by the atomic decay rates because of the metastable lower levels are involved in the gate operations. The Deutsch-Jozsa algorithm is easily realized with current experimental techniques.

Investigation into the structural, elastic and electronic properties for pure zirconium (Zr) crystal had been conducted by the first-principles pseudopotential method based on density functional theory. Both methods, local density approximation (LDA) and generalized gradient approximation (GGA), had been applied on the geometrical optimization of pure Zr to address the difference between two methods and their applicabilities. The result elucidated LDA could match the experimental data better, compared with method GGA. What's more, the structural properties under pressure had been stimulated and analyzed, showing crystal lattice parameters and crystalline volume change nonlinearly within the external pressure. In contrast, the single point energy of Zr showed a great linear correlation with the changing pressure. The elastic constants of the pure Zr were calculated, proving that Zr would acquire excellent ductibility and mechanical stability under pressure. In addition, the optical properties of zirconium under different pressures were analyzed. The adsorbing coefficient increased with the increasing pressure.

The electronic structure and optical properties of the perovskite oxide $LaAlO_3,$ $SrTiO_3$ and $LaAlO_3 /SrTiO_3$ interfaces were studied by the density functional theory (DFT) based on First-principles plane wave pseudopotential method. The energy band structure analysis shows that the $(AlO_2)^-/(TiO_2)^0$ interface is insulating with the band gap being 1.888 eV, whereas the $(LaO)^+/(SrO)^0$ interface seems to be a semiconductor or semimetal with the band gap being 0.021 eV. Moreover, we have also investigated optical properties of the $LaAlO_3,$ $SrTiO_3$ and $LaAlO_3/SrTiO_3$ interfaces, the results indicate that the intensities of absorption, reflectivity, and energy loss spectra of $LaAlO_3$ and $SrTiO_3$ are higher than the corresponding intensities of the $LaAlO_3 /SrTiO_3$ interfaces.