A new leapfrog integrator of rotational motion. The revised angularmomentum approach
Abstract
A new algorithm is introduced to integrate the equations of rotational motion. The algorithm is derived within a leapfrog framework and the quantities involved into the integration are midstep angular momenta and onstep orientational positions. Contrary to the standard implicit method by Fincham [Mol. Simul., 8, 165 (1992)], the revised angular momentum approach presented corresponds completely to the leapfrog idea on interpolation of dynamical variables without using any extrapolations. The proposed scheme intrinsically preserves rigid molecular structures and considerably improves stability properties and energy conservation. As is demonstrated on the basis of simulations for water, it allows to reproduce correct results with extra large step sizes of order 5 fs and 10 fs in the cases of energy and temperatureconserving dynamics, respectively. We show also that iterative solutions can be avoided within our implicit scheme shifting from quaternions to the entire rotationmatrix representation.
 Publication:

arXiv eprints
 Pub Date:
 January 1999
 arXiv:
 arXiv:physics/9901025
 Bibcode:
 1999physics...1025O
 Keywords:

 Physics  Computational Physics;
 Physics  Chemical Physics
 EPrint:
 28 pages, 2 figures