iPI 2.0: A universal force engine for advanced molecular simulations
Abstract
Progress in the atomicscale modeling of matter over the past decade has been tremendous. This progress has been brought about by improvements in methods for evaluating interatomic forces that work by either solving the electronic structure problem explicitly, or by computing accurate approximations of the solution and by the development of techniques that use the BornOppenheimer (BO) forces to move the atoms on the BO potential energy surface. As a consequence of these developments it is now possible to identify stable or metastable states, to sample configurations consistent with the appropriate thermodynamic ensemble, and to estimate the kinetics of reactions and phase transitions. All too often, however, progress is slowed down by the bottleneck associated with implementing new optimization algorithms and/or sampling techniques into the many existing electronicstructure and empiricalpotential codes. To address this problem, we are thus releasing a new version of the iPI software. This piece of software is an easily extensible framework for implementing advanced atomistic simulation techniques using interatomic potentials and forces calculated by an external driver code. While the original version of the code (Ceriotti et al., 2014) was developed with a focus on path integral molecular dynamics techniques, this second release of iPI not only includes several new advanced path integral methods, but also offers other classes of algorithms. In other words, iPI is moving towards becoming a universal force engine that is both modular and tightly coupled to the driver codes that evaluate the potential energy surface and its derivatives.
 Publication:

Computer Physics Communications
 Pub Date:
 March 2019
 DOI:
 10.1016/j.cpc.2018.09.020
 arXiv:
 arXiv:1808.03824
 Bibcode:
 2019CoPhC.236..214K
 Keywords:

 Accelerated sampling;
 Geometry optimizers;
 Path integral;
 Molecular dynamics;
 ab initio;
 Physics  Chemical Physics
 EPrint:
 doi:10.1016/j.cpc.2018.09.020