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SPRING

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SPRING = [integer]
Default: SPRING = -5 

Description: SPRING gives the spring constant between the images as used in the elastic band method


SPRING has to be set together with IMAGES if the elastic band method is used to calculate energy barriers between two ionic configurations of a system.

For SPRING = 0, each image is only allowed to move into the direction perpendicular to the current hyper-tangent, which is calculated as the normal vector between two neighboring images. This algorithm keeps the distance between the images constant to first order. It is therefore possible to start with a dense image spacing around the saddle point to obtain a finer resolution around this point.

The nudged elastic band method [1][2] is applied when SPRING is set to a negative value e.g.

SPRING = -5

This is also the recommended setting. Compared to the previous case, additional tangential springs are introduced to keep the images equidistant during the relaxation (remember the constraint is only conserved to first order otherwise). Do not use too large values, because this can slow down convergence. The default value usually works quite reliably.

References

  1. G. Mills, H. Jonsson and G. K. Schenter, Surface Science, 324, 305 (1995)
  2. H. Jonsson, G. Mills and K. W. Jacobsen, Nudged Elastic Band Method for Finding Minimum Energy Paths of Transitions, in Classical and Quantum Dynamics in Condensed Phase Simulations, ed. B. J. Berne, G. Ciccotti and D. F. Coker (World Scientific, 1998)

Related Tags and Sections

IMAGES

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