Campus Units
Chemistry
Document Type
Article
Publication Version
Published Version
Publication Date
2007
Journal or Book Title
Journal of Chemical Physics
Volume
126
First Page
1
Last Page
11
DOI
10.1063/1.2437214
Abstract
In previous research [J. Chem. Phys.111, 3800 (1999)] a Hessian-based integration algorithm was derived for performing direct dynamics simulations. In the work presented here, improvements to this algorithm are described. The algorithm has a predictor step based on a local second-order Taylor expansion of the potential in Cartesian coordinates, within a trust radius, and a fifth-order correction to this predicted trajectory. The current algorithm determines the predicted trajectory in Cartesian coordinates, instead of the instantaneous normal mode coordinates used previously, to ensure angular momentumconservation. For the previous algorithm the corrected step was evaluated in rotated Cartesian coordinates. Since the local potential expanded in Cartesian coordinates is not invariant to rotation, the constants of motion are not necessarily conserved during the corrector step. An approximate correction to this shortcoming was made by projecting translation and rotation out of the rotated coordinates. For the current algorithm unrotated Cartesian coordinates are used for the corrected step to assure the constants of motion are conserved. An algorithm is proposed for updating the trust radius to enhance the accuracy and efficiency of the numerical integration. This modified Hessian-based integration algorithm, with its new components, has been implemented into the VENUS/NWChem software package and compared with the velocity-Verlet algorithm for the H2CO→H2+CO, O3+C3H6, and F−+CH3OOH chemical reactions.
Rights
Copyright 2007 American Institute of Physics. This article may be downlo (aded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
Copyright Owner
American Institute of Physics
Copyright Date
2007
Language
en
File Format
application/pdf
Recommended Citation
Lourderaj, Upakarasamy; Song, Kihyung; Windus, Theresa Lynn; Zhuang, Yu; and Hase, William L., "Direct Dynamics Simulations Using Hessian-Based Predictor-Corrector Integration Algorithms" (2007). Chemistry Publications. 928.
https://lib.dr.iastate.edu/chem_pubs/928
Comments
The following article appeared in Journal of Chemical Physics 126 (2007): 044105, and may be found at doi:10.1063/1.2437214.