FACCTsWe are visiting STC in Berlin! Come and join us at our poster presentation—we look forward to many exciting discussions with you! Also check out all the new ORCA features and the new ORCA Python interface, OPI!
Visit Anneke Dittmer, Bernardo de Souza, and Christoph Riplinger at the SMASH in beautiful Porto! Get the latest information about our quantum chemical NMR toolkit. We look forward to seeing you there!
Robert Pollice#RobSelects paper of the week #JPhysChem: Derivation of a maximum nucleophilicity principle within conceptual density functional theory and its application. #theochem https://doi.org/10.1021/acs.jpca.5c04610
A Conceptual Density Functional Theory-Based Maximum Nucleophilicity Principle
We introduce a variational formulation of nucleophilicity within the framework of conceptual density functional theory (CDFT), thus proposing a maximum nucleophilicity principle (MNP), in formal analogy to the established minimum electrophilicity principle (MEP). Starting from a third-order Taylor expansion of the electronic energy with respect to the number of electrons at constant external potential, we extend our recently proposed global nucleophilicity index NG derived from the chemical potential μ, hardness η, and hyperhardness γ. We demonstrate that this index follows a well-defined variational condition for electron-loss processes. An explicit functional differential expression is derived for NG[N, v(r)], enabling a thermodynamically consistent description of nucleophilic behavior. The principle is evaluated across a set of six benchmark reactions. The results confirm the concurrent validity of MNP and MEP as complementary conceptual tools for understanding electron transfer in chemical reactivity.
Hot off the press: “A Two-Level Preconditioner for the CASSCF Linear-Response Equations” by our scientific advisor Benjamin Helmich-Paris (MPI Kofo). Its already part of ORCA 6.1, check it out!
ORCA 6.1 will be released tomorrow after the online event to which you are all invited! As a final appetiser, we have a sneak preview of some new methods that will be available in the new version.
#ORCA61 #ORCAqc #CompChem #QuantumChem #TheoChem #FACCTs #MPIKOFO #ChemSky #CompChemSky
Beilstein-InstitutMeet our Managing Editor Dr. Marc Kielmann at Aromaticity 2025 in Mérida, Mexico 🇲🇽, Jan. 27–30, 2025. He is excited to chat with you about #OrganicChemistry, #ScientificPublishing and #OpenAccess.
➡️ https://www.beilstein-journals.org/bjoc/news/M5CP5RLBB3CBT6Z4L4NMJFHTHA?M=y
#Aromaticity2025 #TheoreticalChemistry #ComputationalChemistry #OrganicChemistry #PhysicalChemistry #QuantumChemistry #ChemTwitter #CompChem #TheoChem #aromaticity
#BJOC 💎 🔓
Meet our Managing Editor Dr. Marc Kielmann at Aromaticity 2025 in Mérida, Mexico 🇲🇽, Jan. 27–30, 2025. He looks forward to chatting with you about #OrganicChemistry, #ScientificPublishing and #OpenAccess.
➡️ https://www.beilstein-journals.org/bjoc/news/M5CP5RLBB3CBT6Z4L4NMJFHTHA?M=y
#Aromaticity2025 #TheoreticalChemistry #ComputationalChemistry #OrganicChemistry #PhysicalChemistry #QuantumChemistry #ChemTwitter #CompChem #TheoChem #aromaticity
#BJOC 💎 🔓
Stijn De BaerdemackerEver wonder how a degree in #physchem #theochem or #compchem can lead to a rewarding career in science and industry? Join us tomorrow at 14h00 EST for the next PTC virtual seminar featuring Thomas Prescott (D-wave) and Pierpaolo Morgante (IoP publishing).
More info can be found at
https://www.cheminst.ca/cic-virtual/seminar-series/ptc-virtual-seminar/
Lemme do a Titou with a Titou preprint:
[2308.14618] Seniority and Hierarchy Configuration Interaction for Radicals and Excited States #compchem #theochem @TitouLoos
Seniority and Hierarchy Configuration Interaction for Radicals and Excited States
Hierarchy configuration interaction (hCI) has been recently introduced as an alternative configuration interaction (CI) route combining excitation degree and seniority number, which showed to efficiently recover both dynamic and static correlations for closed-shell molecular systems [\href{https://doi.org/10.1021/acs.jpclett.2c00730}{\textit{J.~Phys.~Chem.~Lett.}~\textbf{2022}, \textit{13}, 4342}]. Here, we generalize hCI for an arbitrary reference determinant, allowing calculations for radicals and for excited states in a state-specific way. We gauge this route against excitation-based CI (eCI) and seniority-based CI (sCI) by evaluating how different ground-state properties of radicals converge to the full CI limit. We find that hCI outperforms or matches eCI, whereas sCI is far less accurate, in line with previous observations for closed-shell molecules. Employing the second-order Epstein-Nesbet (EN2) perturbation theory as a correction significantly accelerates the convergence of hCI and eCI. We further explore various hCI and sCI models to calculate excitation energies of closed- and open-shell systems. Our results underline that both the choice of the reference determinant and the set of orbitals drive the fine balance between correlation of ground and excited states. State-specific hCI2 and higher order models perform similarly to their eCI counterparts, whereas lower orders of hCI deliver poor results, unless supplemented by the EN2 correction, which substantially improves their accuracy. In turn, sCI1 produces decent excitation energies for radicals, encouraging the development of related seniority-based coupled-cluster methods.
Enthalpiste#theochem #moleculardynamics #research #recherche
(copie d'un post twitter)
Je suis les séminaires de recherche reproductible et cette conf de @arnaudlegrand17
sur Org mode et les cahiers de labo est très cool: https://videos.univ-grenoble-alpes.fr/video/27179-a_legrand_01_06_23_orgmodemp4/
Bon moi je suis sur neovim mais les remarques sur jupyter, RStudio et l'apparition des normes sont (très) pertinentes.
Cahier de labo, document computationnel, article reproductible. Emacs/Org-mode: One ring to rule them all? Arnaud Legrand
Cahier de labo, document computationnel, article reproductible. Emacs/Org-mode: One ring to rule them all? Arnaud legrand, chercheur au Laboratoire d’Informatique de Grenoble dans l’équipe POLARIS Les notebooks Jupyter ou Mathematica, l’IDE Rstudio… Ajouté par: Céline Acary-Robert