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Kalypso


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OS: Windows

License: Freeware





Kalypso is a highly-visual Windows software package for molecular dynamics (MD) simulations of atomic collisions in (primarily) metallic and bimetallic crystals. Kalypso comprises a simulation engine of the same name, and various supporting utility programs.

Unlike most MD packages, Kalypso is mainly designed for non-equilibrium MD simulations of (metallic) systems that include surface-vacuum interfaces.

Kalypso uses many-body potentials of the embedded atom method (EAM) type which can describe the material and cohesive properties of fcc metals, hcp metals, bcc metals, some impurities in these metals, and bimetallic systems (alloys, films, clusters, multilayers).

Kalypso will be of interest to researchers who are in the business of doing experiments with ions (e.g. ion bombardment, sputtering, ion scattering) that require interpretation in terms of an atomistic model, and to researchers of nanoscale phenomena in metallic systems. Kalypso can also be used to carry out theoretical enquiries of a more general nature that have no connection to particular experiments, e.g. how do sputtering at glancing and normal projectile incidence differ?

Kalypso permits the modelling of the time evolution of a system that is defined by certain initial conditions and an interaction model. The simulation of events following each incident projectile trajectory is described as a 'run'. For example, a sputtering simulation might consist of 1000 runs, each lasting for 2000 fs. The initial conditions at the start of each run will be quite similar, except for the starting position (impact parameter) of the projectile, which will sample different impact points within the surface unit cell.

The program uses the Verlet integration algorithm with an adaptive timestep to integrate the classical equations of motion for a system of interacting particles. The output from the simulation is a set of particle coordinates and velocities at one or more specified sampling intervals which are stored in the 'dynamics' (or 'trajectory') file.

Various inelastic effects can be incorporated into the simulations, including temperature clamping or programming (with the Berendsen thermostat), electronic stopping, projectile Auger neutralization, lattice site springs, image potential effects.

Kalypso is not designed to simulate specific experiments, so it is up to the user to manipulate the output trajectory data in a way that can be compared with experimental data (if that is the purpose of the simulation). It is quite easy to generate simulation data, but it is usually more difficult to extract meaningful output in the form of scattering profiles, spectra and so forth. A utility program supplied with the package (Winnow) can be used for most tasks.

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