ORBKIT - A Modular Python Toolbox for Cross-Platform Post-Processing of Quantum Chemical Wavefunction Data

TL;DR

ORBKIT is a modular, open-source Python toolbox that enables flexible post-processing of quantum chemical wavefunction data, allowing calculation of various electronic properties on arbitrary grids from standard output files.

Contribution

It introduces a highly modular and extendable Python-based framework for post-processing quantum chemical data across multiple platforms.

Findings

Supports calculation of diverse electronic properties

Offers compatibility with major quantum chemistry programs

Provides flexible, user-extendable modules

Abstract

ORBKIT is a toolbox for post-processing electronic structure calculations based on a highly modular and portable Python architecture. The program allows computing a multitude of electronic properties of molecular systems on arbitrary spatial grids from the basis set representation of its electronic wavefunction, as well as several grid-independent properties. The required data can be extracted directly from the standard output of a large number of quantum chemical programs. ORBKIT can be used as a standalone program to determine standard quantities, for example, the electron density, molecular orbitals, and derivatives thereof. The cornerstone of ORBKIT is its modular structure. The existing basic functions can be arranged in an individual way and can be easily extended by user-written modules to determine any other desired quantities. ORBKIT offers multiple output formats that can be processed by common visualization tools (VMD, Molden, etc.). Additionally, ORBKIT possesses routines to order molecular orbitals computed at different nuclear configurations according to their electronic character and to interpolate the wavefunction between these configurations. The program is open-source under GNU-LGPLv3 license and freely available at http://sourceforge.net/projects/orbkit/. This article provides an overview of ORBKIT with particular focus on its capabilities and applicability, and includes several example calculations.