Fourier-transform infrared spectroscopy has been used for the first time to study the adsorption of chlorofluoromethane ($CH_2ClF$)  on $TiO_2$ at room temperature. The obtained spectra allow to deduce that the adsorbate-substrate interaction occurs through both the $Cl$ and $F$ atoms of the molecule and the surface Lewis acid site $(Ti^{4+}$) and by means $H$-bonds involving the $CH_2$ group and the surface Lewis basic sites ($O^{2-}$ or OH$^-$). In order to better comprehend these interactions, a periodic quantum-mechanical study at DFT/B3LYP level has been carried out by considering the anatase (101) surface and focusing the attention on the determination of the energetically possible adsorbate-substrate structures. According to the comparison between the experimental and calculated vibrational frequencies, it can be concluded that the molecule can adsorb on the surface both through the $Cl$ atom and an $H$-bond and by means the $F$ atom and two $H$-bonds.

A modification of the Slater's atomic orbital theory (AOT) is presented in this paper and applied to the calculation of energies for (1$sns$)$^1S^e$, (1$snp$)$^1P^o$, (1$snd$)$^1D^e$ and ($ns^2$)$^1S^e$, ($np^2$)$^1D^e$, ($nd^2$)$^1G^e$, ($nf^2$)$^1I^e$, ($ng^2$)$^1K^e$, ($nh^2$)$^1M^e$ excited states of He-like ions up to $Z$ = 12. The inadequacy of Slater's AOT for excited states of the atomic systems is discussed. The results obtained in the present work are in good agreement with available experimental and theoretical results.

A mathematical rate equation model using a Monte Carlo simulation has been used to analyze the laser optogalvanic signals of neon waveforms excited at 638.3 nm and 650.7 nm and arising from the $1s_{4}$ state transitioning to $2p_{7}$ and $2p_{8}$ states, respectively. The decay rates have been determined for the directly involved $1s_{4}$ state and also for the indirectly involved $1s_{2}$ and $1s_{5}$ states. There is good agreement among the decay rate constants found and they show a predominantly linear variation with increasing current.

Crystalline and amorphous $BC_2N$ supercells with 216 atoms have been constructed by random distributions of $B,$ $C,$ and $N$ atoms in the diamond lattice and amorphous sp$^3$ carbon structure, respectively. The atomic structures of these two systems were relaxed using density functional theory, and their mechanical properties including the bulk modulus, shear modulus, and Young's modulus were computed. Crystalline $BC_2N$ possess higher elastic moduli than those of cubic $BN.$ Amorphous $BC_2N$ exhibit reasonable elastic moduli and appreciable ductility with a large ratio between the bulk modulus and shear modulus. Both crystalline and amorphous $BC_2N$ are superior candidates as superhard materials.

In a recent calculation on $K_{\alpha}$ transition properties of fluorine-like ions (10 $\leq$ Z $\leq$ 79) by Sur et al. [Phys. Rev. A 77 (2008) 052502], it was found that there is a crossover between $K_{\alpha1}$ and $K_{\alpha2}$ transition probabilities with increasing of atomic number Z. In order to examine this unusual behavior, a further theoretical study has been carried out by using multi-configuration Dirac-Fock (MCDF) method. In the calculation, Breit interaction, electron correlation and quantum electrodynamics (QED) effects have been included. The present study shows a contrary conclusion to the earlier theoretical results.

The elastic and optical properties of the cubic $CeO_2$ and its behavior under pressure are investigated by using the local density approximation (LDA). The computational results are found in good agreement with the available experimental data and other theoretical results. The optical properties including dielectric function, absorption, reflectivity and refractive index are calculated and analyzed. It is found that $CeO_2$ is transparent from the partially ultra-violet to the visible light area and the transparence is hardly affected by the pressure. Furthermore, the curve of optical spectrum shifts to high energy area (blue shift) with increasing pressure.

The geometries of the lowest-lying isomers of small $Au_nTe_m$ $(n, m=1, 2)$ clusters are determined through the MP2 method. The aspect of gold-telluride interaction, the electron correlation and relativistic effects on geometry, and cluster growth are investigated at the MP2 and CCSD(T) theoretical levels. The results show that the gold-telluride interaction is strong enough to modify the known pattern of bare gold clusters. The electron correlation and relativistic effects are responsible not only for gold-gold attraction but also for additional gold-telluride interaction. Both electron correlation and relativistic effects are essential for determining the geometry and cluster growth of coinage metal telluride compound clusters $Au_nTe_m$.

Two-dimensional modified Peierls-Nabarro dislocation equation concerning the discreteness of crystals is reduced to one-dimensional equation to determined the core structure of partial dislocation in Ag. The generalized stacking fault energy along the Burgers vectors of partial dislocation is a skewed sinusoidal force law, which is related to the intrinsic stacking fault energy and the unstable stacking fault energy. A trial solution appropriate for arbitrary dislocation angle is presented within the variational method. The results show that the half core width increases as the increase of dislocation angle. Moreover, the core width decreases with the increase of the unstable stacking fault energy and the intrinsic stacking fault energy. Peierls stress for $60^{\circ}$ partial dislocation is in agreement with the experimental results.

We present a physics scheme for transferring an unknown atomic entangled state via cavity QED. In the transfer process the interaction between atoms and a single-mode nonresonant cavity with the assistance of a strong classical driving field (substitute) replace the Bell-state measurements. The scheme is insensitive to both the cavity decay and the thermal field. In addition, the success probability can reach 1.0 in our scheme.

The electronic structure of rutile $TiO_2$ doped with double nitrogen atoms is studied by the plane-wave ultrasoft pseudopotential method based on the first-principles density functional theory. It has been used to analyze the effect of three doping positions of double $N$ on the relevant band structure. The calculation demonstrates that there exist additional states in the band gap when doping of the rutile $TiO_2$ with $N$ atoms, and the gap become narrowing. The results imply that the doped two $N$ atoms in the adjacent position form a more intermediate stable level, and the total energy is the minimum.