<?xml version="1.0" encoding="utf-8" standalone="yes"?><rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>QTAIM | QTCOVI – Theoretical and Computational Chemistry</title><link>https://qtcovi.github.io/tag/qtaim/</link><atom:link href="https://qtcovi.github.io/tag/qtaim/index.xml" rel="self" type="application/rss+xml"/><description>QTAIM</description><generator>Hugo Blox Builder (https://hugoblox.com)</generator><language>en-us</language><lastBuildDate>Mon, 01 Jan 2024 00:00:00 +0000</lastBuildDate><image><url>https://qtcovi.github.io/media/icon_hu11734318148517933569.png</url><title>QTAIM</title><link>https://qtcovi.github.io/tag/qtaim/</link></image><item><title>NNAIMQ</title><link>https://qtcovi.github.io/software/nnaimq/</link><pubDate>Mon, 01 Jan 2024 00:00:00 +0000</pubDate><guid>https://qtcovi.github.io/software/nnaimq/</guid><description>&lt;h2 id="about">About&lt;/h2>
&lt;p>&lt;strong>NNAIMQ&lt;/strong> predicts QTAIM (Bader) partial charges for C, H, O and N atoms in neutral, singlet-spin gas-phase organic and biological molecules. It comprises four Artificial Neural Networks (one per element) fitted to high-quality quantum chemical data.&lt;/p>
&lt;p>Key features:&lt;/p>
&lt;ul>
&lt;li>High-accuracy QTAIM charges without running a full topological analysis.&lt;/li>
&lt;li>Supports standard &lt;code>.xyz&lt;/code> geometry files as input.&lt;/li>
&lt;li>Compatible with x86-64 and ARM (Apple M1) processors.&lt;/li>
&lt;/ul>
&lt;h2 id="requirements">Requirements&lt;/h2>
&lt;ul>
&lt;li>Python ≥ 3.7.3&lt;/li>
&lt;li>&lt;code>keras&lt;/code>, &lt;code>matplotlib&lt;/code>, &lt;code>numpy&lt;/code>, &lt;code>pandas&lt;/code>, &lt;code>seaborn&lt;/code>, &lt;code>tensorflow&lt;/code>&lt;/li>
&lt;/ul>
&lt;h2 id="usage">Usage&lt;/h2>
&lt;div class="highlight">&lt;pre tabindex="0" class="chroma">&lt;code class="language-bash" data-lang="bash">&lt;span class="line">&lt;span class="cl">&lt;span class="nb">cd&lt;/span> code/
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">python nnaimq.py input
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>where &lt;code>input&lt;/code> is a plain-text file listing the &lt;code>.xyz&lt;/code> geometry files to process.&lt;/p>
&lt;h2 id="links">Links&lt;/h2>
&lt;ul>
&lt;li>&lt;a href="https://github.com/QTCOVI/NNAIMQ" target="_blank" rel="noopener">GitHub repository&lt;/a>&lt;/li>
&lt;/ul></description></item><item><title>PROMOLDEN</title><link>https://qtcovi.github.io/software/promolden/</link><pubDate>Mon, 01 Jan 2024 00:00:00 +0000</pubDate><guid>https://qtcovi.github.io/software/promolden/</guid><description>&lt;h2 id="about">About&lt;/h2>
&lt;p>&lt;strong>PROMOLDEN&lt;/strong> is our in-house code for the topological analysis of scalar fields derived from the electron density and pair density. It implements:&lt;/p>
&lt;ul>
&lt;li>&lt;strong>QTAIM basin integration&lt;/strong> — atomic charges, volumes, and energies from IQA.&lt;/li>
&lt;li>&lt;strong>IQA energy decomposition&lt;/strong> — intra-atomic self-energies and inter-atomic electrostatic/exchange–correlation interactions.&lt;/li>
&lt;li>&lt;strong>Delocalization and localisation indices&lt;/strong> — bond orders from the electron pair density.&lt;/li>
&lt;li>&lt;strong>Non-covalent interaction (NCI) index&lt;/strong> — identification and visualisation of van der Waals, hydrogen bond, and steric interaction regions.&lt;/li>
&lt;li>&lt;strong>Electron localisation function (ELF)&lt;/strong> — topological analysis of electron pairing.&lt;/li>
&lt;/ul>
&lt;h2 id="availability">Availability&lt;/h2>
&lt;p>PROMOLDEN is available for academic use upon request to the PI. Please contact &lt;a href="mailto:ampendas@uniovi.es">ampendas@uniovi.es&lt;/a> to obtain the code and documentation.&lt;/p>
&lt;h2 id="citation">Citation&lt;/h2>
&lt;p>If you use PROMOLDEN in published work, please cite:&lt;/p>
&lt;blockquote>
&lt;p>Á. Martín Pendás, E. Francisco, &lt;em>PROMOLDEN: A QTAIM/IQA code&lt;/em>, University of Oviedo, 2021.&lt;/p>
&lt;/blockquote></description></item><item><title>Quantum Chemical Topology</title><link>https://qtcovi.github.io/research/quantum-chemical-topology/</link><pubDate>Mon, 01 Jan 2024 00:00:00 +0000</pubDate><guid>https://qtcovi.github.io/research/quantum-chemical-topology/</guid><description>&lt;h2 id="overview">Overview&lt;/h2>
&lt;p>Quantum Chemical Topology (QCT) encompasses a family of methods that use the topology of scalar fields derived from the electron density—such as the gradient of ρ(r), the electron localisation function (ELF), or the non-covalent interaction (NCI) index—to partition molecular space into chemically meaningful regions (atoms, bonds, rings, cages).&lt;/p>
&lt;p>The cornerstone of QCT is Bader&amp;rsquo;s &lt;strong>Quantum Theory of Atoms in Molecules (QTAIM)&lt;/strong>, which defines atoms as basin-like regions bounded by zero-flux surfaces of the electron density gradient. Critical points of ρ(r) identify bond, ring, and cage features, while integrated atomic properties (charge, kinetic energy, volume) carry well-defined quantum mechanical meaning.&lt;/p>
&lt;h2 id="our-contributions">Our Contributions&lt;/h2>
&lt;ul>
&lt;li>Development of &lt;strong>PROMOLDEN&lt;/strong>, a high-performance code for topological analysis of electron densities and pair densities.&lt;/li>
&lt;li>Systematic study of basin properties and their relationship to bonding descriptors.&lt;/li>
&lt;li>Extension of QCT frameworks to pair and reduced density matrices.&lt;/li>
&lt;/ul>
&lt;h2 id="key-references">Key References&lt;/h2>
&lt;p>Selected publications from the group on quantum chemical topology are listed in the &lt;a href="https://qtcovi.github.io/publication">Publications&lt;/a> section.&lt;/p></description></item><item><title>SchNet4AIM</title><link>https://qtcovi.github.io/software/schnet4aim/</link><pubDate>Mon, 01 Jan 2024 00:00:00 +0000</pubDate><guid>https://qtcovi.github.io/software/schnet4aim/</guid><description>&lt;h2 id="about">About&lt;/h2>
&lt;p>&lt;strong>SchNet4AIM&lt;/strong> is a code designed to train &lt;a href="https://doi.org/10.1063/1.5019779" target="_blank" rel="noopener">SchNet&lt;/a> deep-learning models on atomic (1-body) and pairwise (2-body) properties formulated within the Quantum Theory of Atoms in Molecules (QTAIM). It is built as a targeted modification of &lt;a href="https://github.com/atomistic-machine-learning/schnetpack" target="_blank" rel="noopener">SchNetPack&lt;/a>, retaining only the components relevant for 1p/2p property training.&lt;/p>
&lt;p>Key features:&lt;/p>
&lt;ul>
&lt;li>Train on &lt;strong>atomic&lt;/strong> (charges, energies, volumes) or &lt;strong>pairwise&lt;/strong> (delocalization indices, IQA interaction energies) QTAIM properties.&lt;/li>
&lt;li>Supports &lt;strong>JSON&lt;/strong> and &lt;strong>ASE-SQLite&lt;/strong> database formats.&lt;/li>
&lt;li>Runs on &lt;strong>CPU and GPU&lt;/strong> (GPU recommended for speed).&lt;/li>
&lt;/ul>
&lt;h2 id="installation">Installation&lt;/h2>
&lt;div class="highlight">&lt;pre tabindex="0" class="chroma">&lt;code class="language-bash" data-lang="bash">&lt;span class="line">&lt;span class="cl">git clone https://github.com/QTCOVI/SchNet4AIM.git
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">&lt;span class="nb">cd&lt;/span> SchNet4AIM
&lt;/span>&lt;/span>&lt;span class="line">&lt;span class="cl">pip install -r requirements.txt
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;h2 id="links">Links&lt;/h2>
&lt;ul>
&lt;li>&lt;a href="https://github.com/QTCOVI/SchNet4AIM" target="_blank" rel="noopener">GitHub repository&lt;/a>&lt;/li>
&lt;/ul></description></item><item><title>NNAIMGUI</title><link>https://qtcovi.github.io/software/nnaimgui/</link><pubDate>Sun, 01 Jan 2023 00:00:00 +0000</pubDate><guid>https://qtcovi.github.io/software/nnaimgui/</guid><description>&lt;h2 id="about">About&lt;/h2>
&lt;p>&lt;strong>NNAIMGUI&lt;/strong> (M. Gallegos, University of Oviedo, 2023) is a code for the prediction and visualisation of atomic properties using feed-forward neural network (FFNN) models. It ships with the built-in NNAIMQ model for predicting QTAIM charges of gas-phase neutral singlet molecules containing C, H, O and N atoms, and supports user-supplied custom models for any atomic property of interest.&lt;/p>
&lt;p>Key features:&lt;/p>
&lt;ul>
&lt;li>&lt;strong>Graphical user interface&lt;/strong> for non-expert users, plus command-line mode.&lt;/li>
&lt;li>Built-in &lt;strong>charge equilibration&lt;/strong> to enforce molecular electroneutrality (13 algorithms included).&lt;/li>
&lt;li>Supports user-defined FFNN models for any atomic property.&lt;/li>
&lt;li>Compatible with &lt;strong>Linux and Windows&lt;/strong>.&lt;/li>
&lt;/ul>
&lt;h2 id="installation">Installation&lt;/h2>
&lt;div class="highlight">&lt;pre tabindex="0" class="chroma">&lt;code class="language-bash" data-lang="bash">&lt;span class="line">&lt;span class="cl">pip install git+https://github.com/m-gallegos/NNAIMGUI.git
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;h2 id="citation">Citation&lt;/h2>
&lt;blockquote>
&lt;p>M. Gallegos &lt;em>et al.&lt;/em>, &lt;em>J. Chem. Inf. Model.&lt;/em> (2023). &lt;a href="https://doi.org/10.1021/acs.jcim.3c00597" target="_blank" rel="noopener">https://doi.org/10.1021/acs.jcim.3c00597&lt;/a>&lt;/p>
&lt;/blockquote>
&lt;h2 id="links">Links&lt;/h2>
&lt;ul>
&lt;li>&lt;a href="https://github.com/QTCOVI/NNAIMGUI" target="_blank" rel="noopener">GitHub repository&lt;/a>&lt;/li>
&lt;li>&lt;a href="https://doi.org/10.1021/acs.jcim.3c00597" target="_blank" rel="noopener">Publication&lt;/a>&lt;/li>
&lt;/ul></description></item></channel></rss>