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We have studied the property of single-walled ZnO nanotubes with adsorbed water molecules, and theoretically designed a new sensor for detecting water molecules using single-walled ZnO nanotubes using a combination of density functional theory and the non-equilibrium Green's function method. Details of the geometric structures and adsorption energies of the H2O molecules on the ZnO nanotube surface have been investigated. Our computational results demonstrate that the formation of hydrogen bonding between the H2O molecules and the ZnO nanotube, and adsorption energies of the H2O molecules on the ZnO nanotube are larger than the adsorption energies of other gas molecules present in the atmospheric environment. Moreover, the current-voltage curves of the ZnO nanotube with and without H2O molecules adsorbed on its surface are calculated, the results of which showed that the H2O molecules form stable adsorption configurations that could lead to the decrease in current. These results suggest that the single-walled ZnO nanotubes are able to detect and monitor the presence of H2O molecules by applying bias voltages.

A quantum dynamic calculation on a five-dimensional O2/LiF (001) model system is performed using the multi-configuration time-dependent Hartree method. The obtained results show that the mechanism of rotational and diffractive excitation in details: Comparison with the rotational excited state, the initially non-rotational state is seen to favor the inelastic scattering in the rotational excitation process. The surface corrugation can damp the quantum interferences and produce a greater amount of rotational inelastic scattering at the expense of the elastic process in the rotational excitation process. The diffraction process and the average energy transferred into the rotational and diffractive mode are also discussed.

Calculations have been performed to investigate the pressure-induced solid-solid phase transitions and the mechanical stability for three zinc-blende II-VI semiconductor compounds: ZnS, ZnSe, ZnTe by ab initio plane-wave pseudopotential density functional theory (DFT). Using the generalized gradient approximation (GGA) for exchange and correlation in the scheme of Perdew-Wang 1991 (PW91), the ground state properties and equation of state are obtained, which are well consistent with the experimental data available and other calculations. On the basis of the forth-order Birch-Murnaghan equation of states, the transition pressures P(t) are determined through the analysis of enthalpy variation with pressure. A linear-response approach is used to calculate the frequencies of the phonon dispersion. Finally, by the calculations of phonon frequencies, some thermodynamic properties such as the vibrational contribution to the Helmholtz free energy (F), enthalpy (H), entropy (S), and the heat capacity (C(V)) are also successfully obtained

The elastic constants and thermodynamic properties of diamond are investigated by using the CRYSTAL03 program. The lattice parameters, the bulk modulus, the heat capacity, the Gruneisen parameter, and the Debye temperature are obtained. The results are in good agreement with the available experimental and theoretical data. Moreover, the relationship between V/V(0) and pressure, the elastic constants under high pressure are successfully obtained. Especially, the elastic constants of diamond under high pressure are firstly obtained theoretically. At the same time, the variations of the thermal expansion a with pressure P and temperature Tare obtained systematically in the ranges of 0-870 GPa and 0-1600 K.

The elastic properties of the wurtzite-type aluminum nitride (w-AlN) are investigated by ab initio plane-wave pseudopotential density functional theory method. The pressure dependences of the normalized primitive cell volume V/V-0, the elastic constants c(ij), the aggregate elastic modulus (B, G, E), the Poisson's ratio (nu), and the Debye temperature circle minus(D) are successfully obtained. From the elastic constants of the w-AlN under pressure, we find that the w-AlN should be unstable at higher pressure than 61.33 GPa.

We have investigated the structural and elastic properties of MgB(2) under high pressures using the full-potential linearized muffin-tin orbital (FP-LMTO) scheme within the generalized gradient approximation correction (GGA) in the frame of density functional theory. The calculated pressure dependence of the normalized volume is in excellent agreement with the experimental results. At the same time the elastic constants and acoustic anisotropy as a function of applied pressure are presented. Through the quasi-harmonic Debye model, we also investigate the thermodynamic properties of MgB(2).

By means of both the theory for pressure-induced shifts (PS) of energy spectra and the theory for shifts of energy spectra due to electron-phonon interaction (EPI), the normal-pressure energy spectra of alpha and beta centers of Cr3+ ions for LLGG:Cr3+ and the PSs of R-1 lines and U band of these centers have been calculated at 10 K, respectively. total calculated results are in very good agreement with the experimental data. For LLGG:Cr, the pressure induced low-high crystal-field transition and the reversal of R-1 -line PS take place. The pressure-dependent variation of R-mix(el) (E-2 -T-4(2)) [mixing-degree of \t(2)(2) (T-3(1))e(4)T(2)) and \t(2)(32) E) base-wavefunctions in the wavefunction of R-1 state without EPI] plays a key role for the reversal of R-1 -line PS. The behavior of the pure electronic PS of R-1 line is quite different from that of the PS of R-1 line due to EPI. It is the combined effect of them that gives rise to the total PS of R, line. The comparison between R-1 -line PS's of GSGG:Cr3+ and LLGG:Cr3+ has been made. It is found that a peak of R-1-line PS appears at R-mix(el) (E-2 - T-4(2)) approximate to 0.08.

The elastic constants of superconducting MgB2 are calculated using a molecular dynamics method (MD) with shell model. The lattice parameters, live independent elastic constants, equations of state (EOS), Debye temperature, and bulk modulus of MgB2,are obtained. Meanwhile, the dependence of the bulk modulus B, the lattice parameters a and c, and the unit cell volume V on the applied pressure are presented. It is demonstrated that the method introduced here can well reproduce the experimental results with a reasonable accuracy.

Traditional ligand-field theory has to be improved by taking into account both "pure electronic" contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy). By means of improved ligand-field theory, R-1, R-2, R-3', R-2', and R-1' lines, U band, ground-state zero-field-splitting (GSZFS) and ground-state g factors as well as thermal shifts of R-1 line and R-2 line of yAG:Cr3+ have been calculated. The results are in very good agreement with the experimental data. In contrast with ruby, the octahedron of ligand oxygen ions surrounding the central Cr3+ ion in YAG:Cr is compressed along the [111] direction. Thus, for YAG:Cr3+ and ruby, the splitting of t(2)(3) (4)A(2) (or t(2)(3) E-2) has opposite order, and the trigonal-field parameters of the two crystals have opposite signs. In thermal shifts of R-1 and R-2 lines of YAG:Cr3+, the temperature-dependent contributions due to EPI are dominant.

By means of improved ligand-field theory, the "pure electronic" presure-induced shifts (PSs) and the PSs due to electron-phonon interaction (EPI) of the R-1, R-2, B-1, B-2, B-3, and R-3' lines and the ground-state zero-lield-splitting' of ruby have been uniformly calculated. The calculation results are in very good agreement with all the experimental data. At normal pressure, ruby is a crystal with very strong crystal field. Thus the admixture of vertical bar t(2)(2)(T-3(1))e(4)T(2)> and vertical bar t(2)(32)E > bases in the wavefunction of R-1 level of ruby is small at normal pressure, and it gradually decreases with increasing pressure, which causes the R-1-line PS of ruby to monotonously red shift with approximate linearity. The combined effect of the pure electronic PS of R, line and the PS of R, line due to EPI gives rise to the total PS of R, line. The analyses and comparisons among the features of R-1-line PSs of three laser crystals (ruby, GSGG:Cr3+ and GGG:Cr3+) have been made, and the origin of their difference has been revealed.

Traditional ligand-field theory has to be improved by taking into account both "pure electronic" contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy). By means of improved ligand-field theory, R-1, R-2, R-3', R-2', and R-1' lines, U band, ground-state zero-field-splitting (GSZFS), and ground-state g factors of ruby and/or GSGG: Cr3+ as well as thermal shifts of GSZFS, R-1 line and R-2 line of ruby have been calculated. The results are in very good agreement with the experimental data. Moreover, it is found that the value of cubic-field parameter given by traditional ligand-field theory is inappropriately large. For thermal shifts of GSZFS, R-1 line and R-2 line of ruby, several conclusions have also been obtained.

The quantum vibrational energy-spectra of amide-Is in alpha-protein molecules are calculated by using the discretely nonlinear Schrodinger equation and physical parameters appropriate to the systems on the basis of theory of bio-energy transport. The numerical results for the energy-spectra are basically consistent with the experimental values obtained by the infrared absorption and Raman scattering and emission-spectra of infrared lights of person's hand-fingers. Utilizing the energy-spectra we explain the laser-Raman spectrum from metabolically active E. Coli, and give some features of the infrared absorption of the protein molecules.

By taking into account all the irreducible representations and their components in the electron-phonon interaction (EPI) as well as all the levels and the admixtures of basic wavefunctions within d(3) electronic configuration, the values of all the parameters in the expressions of thermal shift (TS) and thermal broadening (TB) due to EPI for the ground level, R level and R line of MgO:Cr3+ have microscopically been evaluated; and then, TS and TB of R line and various contributions to them have uniformly been calculated. The results are in very good agreement with the experimental data. It is found that all the three terms of TS due to EPI are red shifts; the Raman term is the largest one, and the optical-branch term and neighbor-level term are important for TS; the contribution to TS from thermal expansion is blue shift, which is also important. The R-line TS Of Mgo:Cr3+ comes from the first-order term of EPI. The elastic Raman scattering of acoustic phonons plays a dominant role in R-line TB of MgO:Cr3+. For both TS and TB, it is very important to take into account all the admixtures of basic wavefunctions within d(3) electronic configuration.

For the first time, by taking into account all the irreducible representations and their components in the electron-phonon interaction (EPI) as well as all the levels and the admixtures of wavefunctions within d(3) electronic configuration, the values of parameters in expressions of Raman and optical-branch terms of thermal shifts (TS) due to EPI for three levels, T-4(2) band and T-4(1) band of ruby have been evaluated; the contributions to TS of T-4(2) and T-4(1) broad bands from thermal expansion have also been. calculated; and then, the TS of the peak energies of 'T2 and 4 Ti broad bands have been calculated. The results are in satisfactory agreement with observed data. The values of single-electron reduced matrix elements representing the strengths of EPI of T-4(2) and T-4(1) bands have respectively been determined. For TS of the peak energies of T-4(2) and T-4(1) bands, it is found that the contribution to TS from the second-order term in EPI Hamiltonian is dominant; TS due to EPI of acoustic branches are over two times as much as those of optical branches, and both of them increase rapidly with temperature; the neighbor-level term is insignificant; the contribution to TS from thermal expansion is specially important, and all the three terms of TS of T-4(2) or T-4(1) band axe red shifts.

By making use of the diagonalization of the complete d(3) energy matrix in a trigonally distorted cubic-field and the theory of pressure-induced shifts (PS) of energy spectra, the whole energy spectrum of alpha-Al2O3:Mn4+ and PS of levels have been calculated. All the calculated results are in excellent agreement with the experimental data. The comparison between the results of alpha-Al2O3:Mn4+ and ruby has been made. It is found that on one hand, R-1-line and R-2-line PS of alpha-Al2O3:Mn4+ and ruby are linear in pressure over 0 similar to 100 kbar, and their values of the principal parameter for PS are very close to each other. On the other hand, the sensitivities of R-1-line and R-2-line PS of alpha-Al2O3:Mn4+ axe higher than those of ruby respectively, which comes mainly from the difference between the values of parameters at normal pressure of two crystals; moreover, the expansion of d-electron wavefunctions of alpha-Al2O3:Mn4+ with compression is slightly larger than the one of ruby, and the effective charge experienced by d-electrons of alpha-Al2O3:Mn4+ decreases with compression more rapidly than the one of ruby. In the final analysis, all these can be explained in terms of the facts that the two crystals are doped alpha-Al2O3 with two isoelectronic ions; the strengths of the crystal field and covalency of alpha-Al2O3:Mn4+ are larger than those of ruby respectively, due to the charge of Mn4+ to be larger than that of Cr3+.

On the basis of the unified calculation of the thermal shifts of R1 line, R2 line and ground-state-splitting transition probabilities of direct and Raman processes have theoretically been calculated. The thermal broadenings of R,R' and B line-groups for ruby, by taking into account all the levels and admixtures of wavefunctions within d3 electronic configuration and all the ΓM in electron-phonon interaction,the transition probabilities of direct and Raman processes have theoretically been calculated, The thermal broadenings of R,R' and B line-groups have successfully been interpreted in terms of the direct and Raman processes of acoustic phonons. The theoretically predicted transition probabilities are in good agreement with the experimental ones.

The calculations of the whole energy spectrum and the g factors of the ground state and t(2)(3) E-2 excited state for MgO:V2+ at normal pressure as well as their pressure-induced shifts have been carried out on the basis of the theory of pressure-induced shifts and the diagonalization of the complete d(3) energy matrix in a regular octahedral field. The calculated results are in very good agreement with experimental data. It is found that in the range of 1 bar similar to 100 kbar, the g value of the ground state increases monotonously with pressure, but the g value of t(2)(3) E-2 excited state for MgO:V2+ decreases at first, and then increases. For the first time, the physical essentials of the pressure-induced shifts of g values for the ground state and t(2)(3) E-2 excited state have been thoroughly analyzed and revealed by taking into account the wavefunctions, energy spectra and orbital-angular-momentum reduction factors at various pressures.

By using strong-field scheme, the complete d(5) energy matrix with D-2d symmetry has been constructed. Then, by diagonalization of this matrix at normal and various pressures, the whole energy spectrum [including the ground-state zero-field-splitting (GSZFS)], its PS and the g factor of the ground state for ZnS:Mn2+ have uniformly been calculated. According to the eigenfunctions and PS, the new assignments of five absorption bands have been given. The variation of tetragonal field with pressure makes a main contribution to the pressure-induced shift (PS) of GSZFS of ZnS:Mn2+, which supports the existence of tetragonal Jahn-Teller distortion in ZnS:Mn2+. It is found that when P greater than or equal to 62 kbar, t(2)(4)(T-3(1))e(4)T(1) merges with t(2)e(4) T-2(2), which has to be taken into account in the calculation of PS of the fifth band in the range of 1 bar similar to 95 kbar. It is demonstrated that the Mn2+ ions in ZnS:Mn2+ have tetrahedral coordination, and the difference between zeta and zeta' caused by the covalency effect is very important for GSZFS. The physical essentials of typical levels, GSZFS and their PS have been revealed. By taking into account the influence of covalency on t(2)(3)((4)A(2))e(2)((3)A(2))(4)A(1) and t(2)(3)(E-2)e(2)((3)A(2))E-4, the position of the third absorption band at normal pressure has been estimated.

The calculations of the whole energy spectrum of ZnSe:Ni2+ at normal pressure and pressure-induced shifts of its levels have been carried out on the basis of the theory of pressure-induced shifts and the diagonalization of the complete d(8) energy matrix in a regular tetrahedral field. The calculated results are in very good agreement with experimental data at normal and various pressures. By taking into account the pressure-induced shifts of spectral bands, the new assignments of bands are given. The comparison between the results of ZnSe:Ni2+ and MgO:Ni2+ shows that the covalency of the bonding between Ni2+ and ligands (Se2-) in ZnSe:Ni2+ is obviously stronger than the one of the bonding between Ni2+ and ligands (O2-) in MgO:Ni2+; the expansion of electron wavefunctions of Ni2+ in ZnSe:Ni2+ under pressure is obviously larger than that of Ni2+ in MgO:Ni2+ under pressure. On the basis of these results, the physical origins of the remarkable difference between the pressure-induced shifts of levels of ZnSe:Ni2+ and those of MgO:Ni2+ are explained. It is found that the large expansion of electron wavefunctions and a phase transition of ZnSe:Ni2+ make the pressure-induced shifts of levels of ZnSe:Ni2+ strongly nonlinear.

By using strong-field scheme, the complete d(5) energy matrix with D-2d symmetry has been constructed. Then, by diagonalization of this matrix at normal and various pressures, the whole energy spectrum [including the ground-state zero-field splitting (GSZFS)] and its pressure-induced shift (PS) of ZnTe:Mn2+ have uniformly been calculated. The results are in very good agreement with experimental data. According to the eigenfunctions and PS, the assignments of four absorption bands have been given. By taking into account the effect of different deformations of t(2) and e radial wavefunctions on t(2)(3)((4)A(2))e(2)((3)A(2))(4)A(1) and t(2)(3)(E-2)e(2)((3)A(2))E-4, the position of the third absorption band at normal pressure has been estimated. The tetragonal field is important for GSZFS of ZnTe:Mn2+ and its PS, which supports the existence of tetragonal Jahn-Teller distortion in ZnTe:Mn2+. The physical essentials of typical levels, GSZFS and their PS have been revealed.

The calculations of the whole energy spectrum and the g factor of the ground state for CaO:Ni2+ at normal pressure and their pressure-induced shifts have been carried out on the basis of the theory of pressure-induced shifts and the diagonalization of the complete dg energy matrix in a regular octahedral field. The calculated results are in very good agreement with experimental data. The physical essentials of the pressure-induced shifts of typical levels and g factor for the ground state have been revealed by using the wavefunctions and energy spectra at various pressures.

A new theory of spectral thermal shifts (TS) and thermal broadenings (TB) has been developed. For the first time, by taking into account all the Gamma M in the electron-phonon interaction (EPI), all the levels and the admixtures of wavefunctions within d(3) electronic configuration, the microscopic expressions; of all the parameters in three terms of TS from EPI have been derived; their values for the R-1, R-2 and ground levels of ruby have been evaluated; the contributions to TS from thermal expansion have also been calculated; the transition probabilities of direct and Raman processes have microscopically been calculated; and then, the unified calculation of the TS of R-1 and R-2 lines and zero-field-splitting (ZFS) for the ground state and the TB of R, R' and B line-groups has been accomplished. The results are in very good agreement with a lot of experimental data. It is found that the contributions from the second-order term of EPI Hamiltonian are dominant in the optical-branch term of ZFS and Raman terms of R-1 line, R-2 line and ZFS; the optical-branch terms play an important role in TS and increase rapidly with temperature, and the optical-branch terms of R1 and R2 lines have opposite signs due to the effects of neighbor levels; the neighbor-level terms for R1 and R-2 lines are very important and it is the admixtures of wavefunctions caused by Coulomb and/or trigonal-field and/or spin-orbit interactions that make them nonzero; the contributions to TS from thermal expansion are also important (especially for ZFS).

The unified calculation of the whole energy spectrum and g factor of the ground state for MgO:Cr3+ at normal pressure and their pressure-induced shifts has been carried out on the basis of;the theory of pressure-induced shifts and the diagonalization of the complete d(3) energy matrix in a regular octahedral field. All the calculated results are in very good agreement with a lot of experimental data. For the first time, by using the wavefunctions obtained by diagonalization of the complete energy matrix, the pressure-induced shifts of. g factor have satisfactorily been calculated and explained by microscopic theory. The rates of change of levels with respect to. various parameters and the contributions to levels from various parameters have been calculated. The distinct differences in magnitude and/or sign of pressure-induced shifts of various levels are immediately determined by their characteristic dependencies on the parameters of interactions. The pressure-induced shifts of levels and g factor have provided important criteria for the correctness of the calculations and assignments of the energy spectrum and wavefunctions, and it is quite necessary and important to carry out the unified calculation of the whole energy spectrum and g factor at normal pressure and their pressure-induced shifts.

By using the theory of pressure-induced shifts and the eigenfunctions at normal and various pressures obtained from the diagonalization of the complete d(3) energy matrix adopting C-3v symmetry, g factors of the ground state of ruby and their pressure-induced shifts have been calculated. The results are in very good agreement with the experimental data. For the precise calculation of properties of the ground state, it is necessary to take into account the effects of all the excited states by the diagonalization of the complete energy matrix.

The mistakes in Ref. [3] are pointed out. Some important problems are discussed, and the correct ideas, calculations and results are given. The R-line thermal shift of MgO:V2+ at normal pressure is the algebraic sum of the contribution from electron-phonon interaction and the contribution from thermal expansion. The latter can be calculated by using the thermal expansion coefficient and the pressure-induced shift.

The R line and U band at normal pressure and their pressure-induced shifts of ruby have been calculated by making use of the SCF embedded-cluster discrete variational (DV-X-alpha) method. The calculated results of the spectral pressure-induced shifts of ruby by making use of the crystal-field theory have also been given. The results of the first-principle calculations are in very good agreement with the experimental data and the calculated results by using crystal-field theory. The results of local lattice relaxations around the Cr3+ ion are obtained by the DV-X-alpha calculations.

By using the strong-field scheme, we have calculated all the reduced matrix elements and the matrix elements of the trigonal crystal field and all the matrix elements of the spinorbit interaction for the d(3) electronic configuration. The complete energy matrix of the d(3) configuration in trigonal field has been constructed. This matrix has been diagonalized to fit the experimental optical and microwave spectral data of ruby. The calculated results are in good agreement with the experimental data. In particular, the zero-field splitting 6 of the ground state and the splitting between R-1 and R-2 lines agree very well with the experimental results. The assignments of all the energy levels and the rates of change of the levels with respect to various parameters are given. The contributions from various parameters to a and the splitting between R-1 and R-2 lines are also given.

By making use of the theory for thermal shift of crystal field spectra of rare earth or transition metal ions, taking into account all the contributions adequately, we calculated R line thermal shift of MgO:Cr3+ by fitting experimental data. The results show a good agreement with thermal shift experimental data and a series of other experimental data of MgO:Cr3+. Values of the most important parameters are calculated theoretically with wavefunctions obtained from diagonalization of complete d3 energy matrices. They are in good agreement with those from fitting experimental data.

The thermal shift of crystal field spectra of rare earth or transition metal ions includes four contributions of different characteristics. In this paper we develop a theory of calculating all those contributions in detail. The contributions to thermal shift consist of that of thermal expansion and those of electron-phonon interaction. The thermal shift caused by thermal expansion is interpreted and calculated by making use of theory of pressure-induced spectral shift. The contribution of phonons of optical branches is given by using single frequency model. The contributions of phonons of acoustic branches include two terms, which are derived by taking into account contributions of all the GAMMAgamma in electron-phonon interaction. The theoretical formulas for parameters in the most important term are given.

The quasiregular model is improved. Using the thermodynamic condition of phase equilibrium we obtain the equations of solid-liquid phase equilibrium curves. The phase diagrams for 11 binary alkali halide system having common anion have been obtained. The eutectic point of each phase diagram is also calculated. The results show that the agreement of theoretical curves with the experimental results is good (except the system CsBr-NaBr).

Vinet equation, Couchman-Reynolds equation and Birch equation are tested and compared by using the data of compressibility for 29 kinds of metals and 9 alkali halide compounds. The results show that the Vinet equation is the best one among three equations, and its universality is very prominent.