The Green's-function Monte Carlo method has been used to calculate the properties of ground-state $^{4}\mathrm{He}$ with several modern potentials. One potential, dubbed HFDHE2, by Aziz et al., gave very good agreement experimental equation state in both liquid and crystal phases. Other such as structure factor momentum distribution also compare well experiment. In phases, perturbative estimates three-body Axilrod-Teller potential were computed. When they are added two-body energies, total...

A Monte Carlo method is used to compute the properties of fluid and crystal phases Lennard-Jones model $^{4}\mathrm{He}$ at absolute zero. The yields exact results subject only statistical sampling errors. energy, structure factor, momentum distribution are calculated several densitites in both phases. In addition, phase we have carried out a detailed study single-particle function. densities which melting freezing occurs determined. perturbative estimates three-body Axilrod-Teller potential...

The Green's function Monte Carlo and variational methods have been used to calculate the properties of ground state two-dimensional liquid solid $^{4}\mathrm{He}$ described by HFDHE2 potential. equation state, melting freezing transition, radial distribution functions in solid, momentum are all presented. Comparisons made with three-dimensional classical systems.

The momentum distribution and condensate fraction of liquid solid 4 He determined from Green's function Monte Carlo calculations using the HFDHE2 pair potential are described. one-body density matrix for 3 derived variational fixed-node also reported.

A theoretical investigation of the energetics and dynamics O(1D)+H2 reaction is reported. Two different valence bond diatomics-in-molecules potential energy surfaces were used which differed only in presence or absence a small barrier to C2v approach. The results quasiclassical trajectory calculations completely on two showed that this exothermic are sensitive features surface at large internuclear distances. Reactions found occur by possible mechanisms. In one mechanism, oxygen atom...

Rate constants for the recombination reaction H + M→H2 M are calculated within framework of resonance complex theory a variety third bodies (M=H, He, Ar, and H2). The stabilization cross sections bimolecular collisions with highly excited orbiting states H2 were computed from exact three-dimensional classical trajectories. Calculations carried out several different reasonable potential surfaces in order to determine effects variations interaction upon macroscopic rate constant. For example,...

The dynamics of collinear collisions F with D2(n 1 a=0) have been studied using standard quasiclassical trajectory and classical S-matrix (semiclassical) techniques for collision energies ranging from 0.65 to 5.50 kcal mole−1 in the center-of-mass system. results are compared previous quantum mechanical calculations on same potential energy surface. At most only three transitions (NR 0→0, R 0→3, 0→4) ``classically allowed'' at any studied. Of these, transition which ``uniform semiclassical''...

Green's-function Monte Carlo and variational methods are used to calculate the properties of a monolayer helium on smooth graphite substrate. We find that in all respects these very close those two-dimensional helium. There small differences equations state two systems. use results show how accurate chemical potentials can be constructed for particles second third layers we compute densities at which will begin form. These good agreement with experimental values.

The equation of state hard hyperspheres in four and five dimensions is calculated from the value pair correlation function at contact, as determined by Monte Carlo simulations. These results are compared to equations obtained molecular dynamics theoretical approaches. In all cases agreement excellent.

Molecular dynamics and Monte Carlo simulations are performed for four- five-dimensional hard hyperspheres at a variety of densities, ranging from the fluid state to solid regime A(4), D(4), D(4)*, D(5) lattices. The equation state, radial distribution functions, average number in coordination layer determined. equations excellent agreement with values obtained both theoretical approaches other simulations. results predictions different function gives better insight about transition than state.

The structure of hard, hyperspherical fluids in dimension one, two, three, four, and five has been examined by calculating the pair correlation function using a Monte Carlo simulation. functions match known results three dimensions. contact value all different dimensions agrees well with theory Song, Mason, Stratt [J. Phys. Chem. 93, 6916 (1989)]. decrease ordering as is increased readily apparent function.

A class of uniform pseudorandom number generators is proposed for modeling and simulations on massively parallel computers. The algorithm simple, nonrecursive, easily transported to serial or vector We have tested the procedure uniformity, independence, correlations by several methods. Related, less complex sequences passed some these tests well enough; however, inadequacies were revealed in an interesting application, namely, annealing from initial lattice that mechanically unstable. In...

The equation of state hard hyperspheres in nine dimensions is calculated both from the values first ten virial coefficients and a Monte Carlo simulation pair correlation function at contact. results are excellent agreement. In addition, we find that series appears to be dominated by an unphysical singularity or singularities on near negative density axis, qualitative agreement with recently solved Percus-Yevick dimensions.

The Green's-function Monte Carlo method is used to investigate the ground-state properties of hcp phase $^{4}\mathrm{He}$ with Lennard-Jones potential. Within errors calculation, about 0.05 K, equation state cannot be distinguished from that fcc reported earlier. Other are essentially same as well. significant discrepancies between experimental and computed equations must due