Adaptive nudged elastic band approach for transition state calculation

We present a method for the location of transition states in complicated physical systems. Our algorithm is a variation of the well-established nudged elastic band method and leads to significant improvements in efficiency and accuracy. We assess the applicability of our method by testing it on several systems of practical interest representing a variety of physical situations. At the molecular level, we apply the method to tautomerization processes in nucleic acid bases and the double proton transfer in nucleic acid base pairs. For bulk systems, we considered the concerted exchange mechanism in Si, which is a complicated pathway for defect-free diffusion in the diamond lattice. For surface systems, we considered ad-dimer diffusion mechanisms on Si(100). We incorporated the climbing image extension of the nudged elastic band method and compared it against the original approach on two-dimensional model potential energy surfaces. Based on favorable comparisons with related methods and the general implementation of our method, we believe that this is well suited for efficient estimates of activation barriers with sophisticated electronic structure codes. (C) 2002 American Institute of Physics.