qvasp: A flexible toolkit for VASP users in materials simulations

We have developed a flexible toolkit, named qvasp (quickly use vienna ab-initio simulation package), to assist users to prepare input files and process output files for Vienna Ab-initio Simulation Package (VASP) during materials simulations. Here, we systematically introduced its design architecture and techniques, as well as how to use qvasp to save time and energy during the materials calculations. This program offers a user-friendly Linux-based command-line interface and aims to help users perform various materials simulations through VASP on high performance computing platform, such as structure optimization, single point energy, work function, electronic structure simulations, mechanical and optical property calculations. In particular, this toolkit provides the basic functions to roll up nanotube from nanosheet and cleave surface from bulk, it also provides an interface for users to customize their own workbags (such as constructing heterojunction structure). All features are designed user-friendly, elegantly and efficiently. We believe this toolkit will be helpful for the users in the field of computational materials science. Program summary Program title: qvasp CPC Library link to program files: http://dx.doi.org/10.17632/2v4m39dt3n.1 Licensing provisions: MIT License. Programming language: Fortran95+Bash Nature of problem: In the material simulation process, there is a lack of flexible, free and usercustomizable pre-and post-processing toolkit for Vienna Ab-initio Simulation Package (VASP). Solution method: A Linux-based command-line toolkit was developed to assist VASP users to perform various types of calculations, such as structure optimization, single point energy, work function, electronic structure simulations, mechanical and optical property calculations. It also provides an interface for users to customize their own tool packages. The elegant and user-friendly command line interface makes it as a core set of toolkits with a wide range of applicability in materials simulations. (C) 2020 Elsevier B.V. All rights reserved.