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Switch for Minimisation

If minimization is TRUE, the atom velocities are rescaled by the friction factor t at the end of each integration step and atoms are allowed to move no more than the maximum distance amount specified in ``Maximum position movement per integration step'' during one step (clipping). This clipping prevents local `hot' spots from developing during minimization.

As a results of such a minimization procedure the simulation system constantly looses energy until the system will stay in a local structural minimum at temperature 0K. In such a minimum the total force on each atom vanishes. Usually it is not possible and not necessary to find exactly the local minimum where all forces are zero. A measure of how far away a system is apart from a local minimum may be given by, e.g., the maximum force or the average force of all atoms in the simulation system. The smaller these values are, the closer the system is to the local minimum. During a minimization run these values are printed each analysis step to screen.

Usually, EGO performs the number of integration steps as given in `Number of Integration Steps'. However, it is also possible to specify a stop criterion based on the maximum force or the average force acting on the atoms in the system. This is done with the keyword MINIKRIT in the free format section.


next up previous contents
Next: Switch for Equilibration Up: The Control File Previous: Order of Exclusion List
Helmut Heller
2000-04-19