https://qtcovi.github.io/tag/topological-analysis/Topological AnalysisHugo Blox Builder (https://hugoblox.com)en-usMon, 01 Jan 2024 00:00:00 +0000https://qtcovi.github.io/media/icon_hu11734318148517933569.pnghttps://qtcovi.github.io/tag/topological-analysis/https://qtcovi.github.io/software/critic2/Mon, 01 Jan 2024 00:00:00 +0000https://qtcovi.github.io/software/critic2/<h2 id="about">About</h2> <p><strong>critic2</strong> is an open-source program for the topological analysis of scalar fields—most commonly the electron density—in both molecular and periodic (crystal) systems. It supports a wide range of quantum chemistry and plane-wave DFT codes as input sources.</p> <p>Key capabilities include:</p> <ul> <li><strong>Critical point search</strong> — bonds, rings, and cages from any scalar field.</li> <li><strong>QTAIM integration</strong> — atomic charges, volumes, and multipole moments.</li> <li><strong>Delocalization indices</strong> — from promolecular or DFT-level densities.</li> <li><strong>NCI visualisation</strong> — reduced density gradient isosurfaces for non-covalent interaction analysis.</li> <li><strong>Crystal structure analysis</strong> — symmetry, powder diffraction, intermolecular interaction energies.</li> </ul> <h2 id="links">Links</h2> <ul> <li><a href="https://github.com/aoterodelaroza/critic2" target="_blank" rel="noopener">GitHub repository</a></li> <li><a href="https://aoterodelaroza.github.io/critic2/" target="_blank" rel="noopener">Documentation</a></li> </ul> <h2 id="citation">Citation</h2> <blockquote> <p>A. Otero-de-la-Roza, E. R. Johnson, V. Luaña, <em>Comput. Phys. Commun.</em> <strong>185</strong>, 1007 (2014). A. Otero-de-la-Roza, M. A. Blanco, A. M. Pendás, V. Luaña, <em>Comput. Phys. Commun.</em> <strong>180</strong>, 157 (2009).</p> </blockquote>https://qtcovi.github.io/software/edf-omp/Mon, 01 Jan 2024 00:00:00 +0000https://qtcovi.github.io/software/edf-omp/<h2 id="about">About</h2> <p><strong>edf-omp</strong> computes <strong>Electron Number Distribution Functions</strong> (EDFs) — the probability distribution of finding <em>n</em> electrons in a QTAIM atomic basin. EDFs encode the full statistics of electron population fluctuations, giving direct access to:</p> <ul> <li>Atomic mean electron populations (charges).</li> <li>Electron localisation and delocalization indices.</li> <li>Higher-order cumulants revealing multi-centre bonding and electron correlation.</li> </ul> <p>The code is written in Fortran and parallelised with <strong>OpenMP</strong>, using <strong>LAPACK</strong> for the required linear algebra. It is designed for high-throughput calculations on large systems.</p> <p>The compiled binary is also available at the companion <a href="https://qtcovi.github.io/edf-omp/" target="_blank" rel="noopener">GitHub Pages site</a>.</p> <h2 id="links">Links</h2> <ul> <li><a href="https://github.com/QTCOVI/edf-omp" target="_blank" rel="noopener">GitHub repository</a></li> <li><a href="https://qtcovi.github.io/edf-omp/" target="_blank" rel="noopener">Web page &amp; downloads</a></li> </ul>https://qtcovi.github.io/software/promolden/Mon, 01 Jan 2024 00:00:00 +0000https://qtcovi.github.io/software/promolden/<h2 id="about">About</h2> <p><strong>PROMOLDEN</strong> is our in-house code for the topological analysis of scalar fields derived from the electron density and pair density. It implements:</p> <ul> <li><strong>QTAIM basin integration</strong> — atomic charges, volumes, and energies from IQA.</li> <li><strong>IQA energy decomposition</strong> — intra-atomic self-energies and inter-atomic electrostatic/exchange–correlation interactions.</li> <li><strong>Delocalization and localisation indices</strong> — bond orders from the electron pair density.</li> <li><strong>Non-covalent interaction (NCI) index</strong> — identification and visualisation of van der Waals, hydrogen bond, and steric interaction regions.</li> <li><strong>Electron localisation function (ELF)</strong> — topological analysis of electron pairing.</li> </ul> <h2 id="availability">Availability</h2> <p>PROMOLDEN is available for academic use upon request to the PI. Please contact <a href="mailto:ampendas@uniovi.es">ampendas@uniovi.es</a> to obtain the code and documentation.</p> <h2 id="citation">Citation</h2> <p>If you use PROMOLDEN in published work, please cite:</p> <blockquote> <p>Á. Martín Pendás, E. Francisco, <em>PROMOLDEN: A QTAIM/IQA code</em>, University of Oviedo, 2021.</p> </blockquote>