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Manuscript Title: COOL: a code for Dynamic Monte Carlo Simulation of molecular dynamics
Authors: Paolo Barletta
Program title: COOL
Catalogue identifier: AEHJ_v1_0
Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 182(2011)388
Programming language: C++.
Computer: Desktop.
Operating system: Linux.
RAM: 500 Mbytes
Keywords: DSMC, cold molecules, sympathetic cooling.
PACS: 34.1.0.+x, 37.10.+x, 51.10.+x.
Classification: 16.7, 23.

Nature of problem:
Simulation of the sympathetic process occurring for two molecular gases co-trapped in a deep optical trap.

Solution method:
The Direct Simulation Monte Carlo method exploits the decoupling, over a short time period, of the inter-particle interaction from the trapping potential. The particle dynamics is thus exclusively driven by the external optical field. The rare interparticle collisions are considered with an acceptance/rejection mechanism, that is by comparing a random number to the collisional probability defined in terms of the inter-particle cross section and centre-of-mass energy. All particles in the trap are individually simulated so that at each time step a number of useful quantities, such as the spatial densities or the energy distributions, can be readily evaluated.

The in-trap motion of the particles is treated classically.

Running time:
The running time is relatively short, 1-2 hours. However it is convenient to replicate each simulation several times with different initialisations of the random sequence.