Correlation: An Analysis Tool for Liquids and for Amorphous Solids

Abstract

For almost a century, since Bernal\'s attempts at a molecular theory of liquid structure(Bernal [1]), correlation functions have been the bridge to compare theoretical calculations with experimental measurements in the study of disordered materials. Pair Distribution Functions (g(r)), Radial Distribution Functions (J(r)), Plane Angle Distributions (g({\theta})) and Coordination Numbers (nc) have been widely used to characterize amorphous and liquid materials (Waseda [2]; Elliott [3]; Valladares et al. [4]) and, in particular Bulk Metallic Glasses (Miller and Liaw [5]; Galv\'an-Col\'in et al. [6]). Correlation is an Open-Source software designed to analyze liquid structures and amorphous solids; the software is user-friendly, the modular design makes it easy to integrate in High-Throughput Computing (HTC) to process structures with a large number of constituents in a standardized fashion. Correlation is ready to be used in Windows,Linux and Mac. Currently, we support DMol3 (CAR), CASTEP (CELL), ONETEP (DAT)and VASP (POSCAR) structure files. The code can handle up to 25,000 atoms, so it can be used to analyze both classical and first-principles simulations. At the end, the output of every single correlation function is exported to the corresponding comma-separated value file (CSV), to further analyze the results.