55 research outputs found
Optimized Verlet-like algorithms for molecular dynamics simulations
New explicit velocity- and position-Verlet-like algorithms of the second
order are proposed to integrate the equations of motion in many-body systems.
The algorithms are derived on the basis of an extended decomposition scheme at
the presence of a free parameter. The nonzero value for this parameter is
obtained by reducing the influence of truncated terms to a minimum. As a
result, the new algorithms appear to be more efficient than the original Verlet
versions which correspond to a particular case when the introduced parameter is
equal to zero. Like the original versions, the proposed counterparts are
symplectic and time reversible, but lead to an improved accuracy in the
generated solutions at the same overall computational costs. The advantages of
the new algorithms are demonstrated in molecular dynamics simulations of a
Lennard-Jones fluid.Comment: 5 pages, 2 figures; submitted to Phys. Rev.
A consistent description of kinetics and hydrodynamics of systems of interacting particles by means of the nonequilibrium statistical operator method
A statistical approach to a self-consistent description of kinetic and
hydrodynamic processes in systems of interacting particles is formulated on the
basis of the nonequilibrium statistical operator method by D.N.Zubarev. It is
shown how to obtain the kinetic equation of the revised Enskog theory for a
hard sphere model, the kinetic equations for multistep potentials of
interaction and the Enskog-Landau kinetic equation for a system of charged hard
spheres. The BBGKY hierarchy is analyzed on the basis of modified group
expansions. Generalized transport equations are obtained in view of a
self-consistent description of kinetics and hydrodynamics. Time correlation
functions, spectra of collective excitations and generalized transport
coefficients are investigated in the case of weakly nonequilibrium systems of
interacting particles.Comment: 64 LaTeX2e pages, 1 figure, special sty-files, additional font
XY Spin Fluid in an External Magnetic Field
A method of integral equations is developed to study inhomogeneous fluids
with planar spins in an external field. As a result, the calculations for these
systems appear to be no more difficult than those for ordinary homogeneous
liquids. The approach proposed is applied to the ferromagnetic XY spin fluid in
a magnetic field using a soft mean spherical closure and the Born-Green-Yvon
equation. This provides an accurate reproduction of the complicated phase
diagram behavior obtained by cumbersome Gibbs ensemble simulation and multiple
histogram reweighting techniques.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let
On the problem of a consistent description of kinetic and hydrodynamic processes in dense gases and liquids: Collective excitations spectrum
Based on the generalized non-Markovian equations obtained earlier for a
nonequilibrium one-particle distribution function and potential part of the
averaged enthalpy density [Markiv B.B., Omelyan I.P, Tokarchuk M.V., Condens.
Matter Phys., 2010, 13, 23005] a spectrum of collective excitations is
investigated, where the potential of interaction between particles is presented
as a sum of the potential of hard spheres and a certain long-range potential.Comment: 6 page
- …