A nudged-elastic band (NEB) method is modified with concomitant two climbing images (C2-NEB) to find a transition state (TS) in complex potential energy landscape, using either quantum electronic-structure or classical atomic potential methods. The Fortran module “NEB” contained in the downloadable file “neb.F” implements our C2-NEB algorithm. Our more stable and reliable C2-NEB code is modified from the single climbing image (C1-NEB) open-source code authored by G. Henkelman (U. Texas - Austin). C2-NEB code is implemented to replace NEB subroutine in the VASP plane-wave electronic-structure code (available at http://www.vasp.at/).
Zarkevich, Nikolai A. and Johnson, Duane D., "neb.F (source code)" (2014). Ames Laboratory Software. 1.