Classical trajectory method is used in 1D and 3D models to study classical dynamics of Hydrogen molecular ion (H₂⁺) in intense laser fields. Probabilities of survival, ionization, dissociation and Coulomb explosion and average distance between electron and the mass-center are calculated. It is shown that the 1D model is available for dynamics of hydrogen molecular ion in intense laser fields.

2-order norm-preserving and symplectic scheme and 2-order explicit symplectic scheme for separable and linear Hamiltonian system including explicitly time are constituted and applied to compute interaction of the simulated laser field with an electron in the finite width and infinite depth potential well,the results are in good agreement with theoretical analysis.

The scheme-conservation quantities of the 1-and 2-order explicit symplectic schemes are found according to the quadric-form conservation quantities for Separable and linear Hamiltonian Systems.It can be shown that so long as the time-step is properly small the norm and the energy can keep conservied in certain accuracy.

Gauss numerical integration is applied to compute the radial emission coefficients in Optically-Thick,Cylindrically-Symmetric Plasmas.Using the integration,the generalized Abel equation is separated into a system of linear algebraic equations and the coefficient matrix of the system is an upper triangular matrix,so the interpolation,which has second order of accuracy,is very simple to compute and less computation time is required.

Classical trajectories of diatomic system N₂ are calculated by means of both Symplectic and R-K algorithms.It is shown that Symplectic algorithm keeps Symplectic structure of the system and its intrinsic qualities unchanged and consistent with the theory and experiment. R-K approach is not the case.

A simple example is computed by using R-K approach and step-by-step normalization correction.It is shown that the norm of wave function can be preserved by using this method,However,other physical quantities,such as energy of the system and population probabilities on the states,are still not reasonable,even worse.

The canonic equations of an intense field model are constructed by substituting symmetric difference quotient for partial derivative in Hamiltonian and the numerical solution is found by using square-preserving and symplectic scheme.The result is consistent with theoretical analyses,and shows that the method is successful.It probably overcomes the difficulties that often encountered to intense field model by using conventional difference methods.

The value of potential barrier of H abstraction from hydrogeneted diamond (111) surface is critical to understand nucleation and growth dynamics of diamond film under the condition of Chemical Vapor Deposition.The previous theoretical works on the value are far from accord based upon different MO methods.On use of a series of cluster models and some kinds of MO methods the potential barrier is systematically studied here.After determinating the MNDO approach reliability for this problem,the corrected theoretical value is given as well.

A computational code JLULP1 of plasma produced by laser irradiating rectangular target written by us is reported. By using this code, the spatial distrubutional and time-dependent properties of plasma produced by laser irradiating rectangular Sitarget, and the relations of plasma properties with shapes of target have been investigated for the first time. Comparison with the plasma produced by cylindrical target shows that the plasma produced by rectangular target favours three-body recombination.

In this paper as continuation of our first paper [4], the variational perturbation scheme based on hydrodynamic analogy to Schrödinger equation is adopted and the perturbed wavefunctions for the hydrogen-like atoms H, He⁺, Li⁺², Be⁺³,B⁺⁴ in their excited states (21±1)and (32±2)in a small and time harmonic electric field and the polarizabilities and the 1st resonant frequences are calculated. And the variation of the electronic probability is also discussed. It is shown that the calculated results of the polarizability and the 1st resonant frequence are in good agreement with the exact data. And it is further shown that ∈ and S play the same important role in the calculation of the polarizability using this scheme.

In this paper the variational perturbation scheme based on hydrodynamic analogy to Schrödinger equation is adopted and the perturbed wavefunctions for the hydrogen-like atoms H, He⁺, Li⁺², Be⁺³,B⁺⁴ in their ground state (100)in a small and time harmonic electric field and the polarizabities and the 1st resonant frequences are calculated. And the variation of the electronic probability with time is also discussed. It is shown that the calculated results of the polarizability and the 1st resonant frequence are in good agreement with the exact data and that ∈ and S play the same important role in the calculation of the polarizability by using this scheme.

A difference quotient-numerical integration method is adopted to solve radiative transfer problems in an anisotropic scattering slab medium. By using the method, the radiative transfer problem is separated into a system of linear algebraic equations and the coefficient matrix of the system is a band matrix, so the method is very simple to evaluate on computer and to deduce formulae and easy to master for experimentalists. An example is evaluated and it is shown that the method is precise.

The energy of the ground Li-atom have been computed with the Hartree-Fock finite-element method. The relative error of the HFFEM result and HF limit value is-4.1×10^-4. After considering correlative correct, the relative error of HFFECM value and experimental value is-4.9×10-4.