Efficient Methods for Finding Transition States in Chemical Reactions: Comparison of Modified Dimer Method and Partitioned Rational Function Optimization Method
Engineering, Chemical Engineering, Catalysis and Reaction Engineering, Analytical Chemistry
A combination of interpolation methods and local saddle-point search algorithms is probably the most efficient way of finding transition states in chemical reactions.Interpolation methods such as the growing-string method and the nudged-elastic band are able to find an approximation to the minimum-energy pathway and thereby provide a good initial guess for a transition state and imaginary mode connecting both reactant and product states. Since interpolation methods employ usually just a small number of configurations and converge slowly close to the minimum-energy pathway, local methods such as partitioned rational functionoptimization methods using either exact or approximate Hessians or minimum-mode-following methods such as the dimer or the Lanczos method have to be used to converge to the transition state. A modification to the original dimer method proposed by [Henkelman and Jónnson J. Chem. Phys.111, 7010 (1999)] is presented, reducing the number of gradient calculations per cycle from six to four gradients or three gradients and one energy, and significantly improves the overall performance of the algorithm on quantum-chemical potential-energysurfaces, where forces are subject to numerical noise. A comparison is made between the dimer methods and the well-established partitioned rational functionoptimization methods for finding transition states after the use of interpolation methods. Results for 24 different small- to medium-sized chemical reactions covering a wide range of structural types demonstrate that the improved dimer method is an efficient alternative saddle-point search algorithm on medium-sized to large systems and is often even able to find transition states when partitioned rational functionoptimization methods fail to converge.
Published in The Journal of Chemical Physics, Volume 123, Issue 22, 2005, pages 224101-224114.
© The Journal of Chemical Physics, 2005, American Institute of Physics
Heyden, A., Bell, A. T., Keil, F. J. (2005). Efficient Methods for Finding Transition States in Chemical Reactions: Comparison of Modified Dimer Method and Partitioned Rational Function Optimization Method. The Journal of Chemical Physics, 123(22), 224101-224114.