ORCA Meets Python─The ORCA Python Interface OPI The ORCA program suite is one of the most widely used quantum chemistry software packages. It features a wide range of electronic structure methods and algorithms for the prediction of molecular chemi...

Our paper on the #ORCA #Python Interface OPI is published in #JCTC!

pubs.acs.org/doi/full/10....

Check it out and join the OPI community.

OPI on GitHub: github.com/faccts/opi
OPI documentation: www.faccts.de/docs/opi/docs

#FACCTs #OPI #CompChem #QuantumChem #ScientificSoftware #OpenSource

FACCTs at the Analytica, Munich. Hall A3, Booth 503-1.

Visit our team at the Analytica in Munich to learn more about our latest software solutions. We’re looking forward to connecting and exchanging with you.

Hall A3,
Booth 503-1

#FACCTs #analytica2026 #CompChem #QuantumChem #Workflows #Automation #AI #AnalyticChem #ORCA #WEASEL #TOUCAN

Finding Transition States with NEB-TS - ORCA 6.1 TUTORIALS

Thorsten Gressling will give a presentation on the combination of #ParamusAI and #ORCA for "𝘈𝘶𝘵𝘰𝘮𝘢𝘵𝘦𝘥 𝘙𝘦𝘢𝘤𝘵𝘪𝘰𝘯 𝘔𝘦𝘤𝘩𝘢𝘯𝘪𝘴𝘮 𝘋𝘪𝘴𝘤𝘰𝘷𝘦𝘳𝘺 𝘸𝘪𝘵𝘩 𝘖𝘙𝘊𝘈 𝘢𝘯𝘥 𝘈𝘐 𝘈𝘨𝘦𝘯𝘵𝘴" at the ACS Spring in Atlanta.

Check out NEB-TS in our tutorial: www.faccts.de/docs/orca/6....

#FACCTs #QuantumChem #CompChem #AI #ACS2026

a man with glasses and suspenders is standing in front of a group of people and says science !! ALT: a man with glasses and suspenders is standing in front of a group of people and says science !!

Good news from the Quantum Chemistry group of @ua.es

The local call for funding situated (again!) among the top-3 best performers, a classification strictly based on publications indexed (Web of Science)

@chemortuno.bsky.social

#theochem #compchem #quantumchem

Lectures (3 ECTS, syllabus here 👇🏼) on quantum modelling finished!

Time to continue with undergraduate teaching about computational chemistry and molecular spectroscopy 💪🏼

@ua.es #theochem #compchem #quantumchem

Assessing Isomerization Potential of Plant Protection Products on Leaf Surfaces by Dislodgeable Foliar Residue Studies and a Simple Quantum Chemical Calculation Protocol A small-scale dislodgeable foliar residue (DFR) study setup in the greenhouse was applied and validated to determine the parameters influencing the isomerization of active substances on the leaf surfa...

#WEASEL helps our industry partners at Bayer solve real world challenges using quantum chemistry.

Check out their paper investigating the isomerization potential of plant protection products on leaf surfaces.

pubs.acs.org/doi/full/10....

#QuantumChem #Agrochemistry #PlantProtection #Workflows

The team of Editors of Theor. Chem. Acc. (@springernature.com) is pleased to present the Editor’s Choice Collection (high-quality and relevant manuscripts) for the first quarter of the year 2026. Congratulations to all authors!

link.springer.com/collections/...

#theochem #compchem #quantumchem

Computational Chemistry can be very noisy 😅😬

Teaching today at @ua.es about #DFT calculations of weakly bound systems, using @orca-qc-official.bsky.social and @avogadro.cc

#compchem #theochem #quantumchem

FACCTs at the Analytica 2026

On March 24, #analytica 2026 kicks off in Munich — and we’re excited to be part of it.

Experience #WEASEL, #ORCA, and more live and discover how our solutions elevate your processes to a new level of efficiency.

We look forward to seeing you there

#FACCTs #QuantumChem #Workflows #AnalyticalChem

With our latest #WEASEL release, it is time to introduce another workflow: the fully automated calculation of rotational barriers for arbitrary molecules, enabling the reliable identification and classification of #atropisomers.

www.faccts.de/weasel/

#FACCTs #Workflows #QuantumChem #CompChem #CADD

Slides ready for my next talk! Hosted by @group-ctm.bsky.social @chimieparistechpsl.bsky.social

The title is inspired by a sentence coined by John P. Perdew during his talk at the past #DFT 2017 conference.

Don’t miss the next one! @dft2026eus.bsky.social

#theochem #compchem #quantumchem

Ready to continue with the lectures and hand-ons sessions on quantum and molecular modelling at the @ua.es

We will work with He clusters, fullerenes, nanotubes, isolated and stacked acenes, and Ir(ppy)3, etc.

#theochem #compchem #quantumchem

Two teams, one quest: democratizing quantum chemistry. We’re very happy to support the fantastic team at @thematterlab.bsky.social and to see this great achievement. Many thanks as well for trusting the ORCA quantum chemistry package!

#ORCAqc #QuantumChem #AgenticAI #ElAgente

QUICHE Project - FACCTs The QUICHE project is a UK–Germany Collaboration Bringing Chemistry Software into the Quantum Computing Era

We are proud to be part of the Quantum Integrated Chemistry #QUICHE project, funded by ZIM and Innovate UK. Teaming up with Quantum Motion and Riverlane we strive to enable quantum-ready calculations within #ORCA

Learn more: www.faccts.de/quiche-proje...

#QuantumChem #QuantumComputing #Workflows

Ligand Field Tuning of Photoreactivity: Contrasting Low‐Spin and High‐Spin Fe(III)‐Azido Complexes Why do near-identical Fe(III)-azido complexes exhibit different photoreactivity profiles? Linking spin states and key normal modes to wavelength-dependent photoreductive and photooxidative reaction p...

#CASSCF and (TD-)DFT are well-established components of #ORCA's method portfolio. Check out the new paper by Krewald et al., who use both for tuning the photoreactivity of Fe(III)-azido complexes.

doi.org/10.1002/cptc...

CASSCF in ORCA: www.faccts.de/docs/orca/6....

#ORCAqc #CompChem #QuantumChem

Use Fukui functions to estimate molecular reactivity and pinpoint reactive sites. With #WEASEL, you can visualize them and get all associated indices easily using just one command!

Learn more about WEASEL www.faccts.de/weasel

#FACCTs #CompChem #QuantumChem #Fukui #Reactivity #WorkflowAutomation

FACCTs at EuChemS CompChem 2025

We are excited to be at EuChemS CompChem, Naples!
Join our team to learn more about ORCA and its new Python interface, OPI. Don’t miss Christoph Riplinger’s talk on Tuesday at 15:45.
We’re looking forward to discussing great science with many of you!

#ORCAqc #ORCA #CompChem #QuantumChem #ChemSky

A Two-Level Preconditioner for the CASSCF Linear-Response Equations We present an efficient two-level strategy to accelerate the solution of the CASSCF linear-response eigenvalue problem using a customized Davidson algorithm. By identifying a subset of important response-vector components─the so-called P space─we compute and diagonalize full Hessian and metric matrix elements while treating the remaining Q-space components with a diagonal approximation. This approach decouples the orbital and configuration responses, enabling independent preconditioning of each component. Computational cost is further reduced through the resolution-of-the-identity approximation. We demonstrate significant performance gains across a diverse set of molecules, achieving speedups of up to 2.05 compared to the standard diagonal preconditioning. The largest efficiency gains are observed for MCTDA calculations involving many excited states and relatively small response-vector lengths. The two-level strategy is available in ORCA 6.1 and paves the way for extensions to dynamic polarizabilities, which require solving large-scale linear equations, as well as to time-dependent density functional theory and CI singles.

Hot off the press: “A Two-Level Preconditioner for the CASSCF Linear-Response Equations” by our scientific advisor Benjamin Helmich-Paris (@orca-qc-official.bsky.social). Its already part of ORCA 6.1, check it out!

doi.org/10.1021/acs....

#ORCA #ORCAqc #CompChem #QuantumChem #TheoChem #CASSCF

Pericyclic Umpolung in a Catalytic Asymmetric Diels–Alder Reaction of Tropone with Enol Ethers One remarkable feature of catalysis in chemical synthesis is its capacity to override substrate-imposed reactivity and selectivity. The inversion of normal reaction patterns, commonly known as Umpolun...

Check out the recent paper by List, Neese et al. that ones more demonstrates the synergy of experiment and quantum chemistry powered by ORCA (DFT, GOAT, ...) @faccts.de @orca-qc-official.bsky.social

doi.org/10.1021/jacs...

ORCA: www.faccts.de/orca/

#ORCAqc #ORCA #Catalysis #CompChem #QuantumChem

Excited-state methods based on state-averaged long-range CASSCF short-range DFT In the present work we propose two distinct state-averaging (SA)-based methodologies for the calculation of excited states, in conjunction with the long-range complete active space self-consistent fie...

Check out the recent paper on Excited-state methods based on state-averaged long-range CASSCF short-range DFT by Benjamin Helmich-Paris et al. And how to use it in ORCA 6.1.

doi.org/10.1039/D5CP...

www.faccts.de/docs/orca/6....

#ORCAqc #CompChem #QuantumChem #ChemSky #DFT

#theochem #compchem #quantumchem #DFT #chemsky

Thanks to @springer.springernature.com from compiling the information and made it available to Editors

Our cover for the @jmaterchem.rsc.org is now ready!

#theochem #compchem #quantumchem

Check out the content here:
pubs.rsc.org/en/content/a...

See you there! 🙌🙌
#theochem #compchem #quantumchem

Postdoctoral Fellowships The information provided on this page is a summary of the main rules and requirements for Postdoctoral Fellowships (PFs) and who can apply for them.

We are seeking a candidate to apply for a Marie Curie Actions Postdoctoral Fellowship for the Sep. 10th, 2025, deadline.

The candidate will be building AI models to predict molecular interaction of pre-activated complexes and chemical reactivity.

#compchem
#AI
#quantumchem

Reply here for contact

The CCL (Computational Chemistry List) will close very soon. I still remember my first post there (as a PhD student, 1998 😱) asking about #DFT and non-dynamic correlation. A big thank to Jan for all this work: having such a resource was important in those dates.

#theochem #compchem #quantumchem

Theor. Chem. Acc. has received almost 500 submissions during the first half of 2025! A big thank you to authors and reviewers.

The recently closed and ongoing special collections are an example of modern trends, contributing to the scope of the journal.

#theochem #compchem #quantumchem

ORCA as External Optimizer - ORCA 6.1 TUTORIALS

You can now use g-xTB @grimmelab.bsky.social with ORCA via the ExtOpt feature! Check out our new tutorial and learn how to use it in GOAT, NEB-TS and more.

www.faccts.de/docs/orca/6....

#ORCAqc #FACCTs #gxTB #CompChem #QuantumChem

GitHub - faccts/opi: ORCA Python Interface ORCA Python Interface. Contribute to faccts/opi development by creating an account on GitHub.

Create input and parse output of ORCA with the new ORCA Python Interface (OPI), an open source project supported by FACCTs. Check it out and become part of the OPI community!

GitHub: github.com/faccts/opi
Docs: www.faccts.de/docs/opi/1.0...

#ORCAqc #Python #FACCTs #CompChem #QuantumChem

Theor. Chem. Acc. will dedicate a special issue to the memory of Bogumił Jeziorski, with great colleagues acting as guest editors! Thank you for this nice initiative and for considering this journal as the appropriate forum.

#theochem #compchem #quantumchem

link.springer.com/journal/214

FACCTs FACCTs is bringing the ORCA software to industry - promoting the next Quantum leaps in the Pharma, Materials and Chemical Industries.

Missed the ORCA 6.1 release event? All talks are now online on our YouTube channel!

www.youtube.com/@faccts_orca

ORCA 6.1 Release Event Playlist:

www.youtube.com/watch?v=mRSk...

#ORCA61 #ORCAqc #FACCTs #MPIKOFO #CompChem #QuantumChem #ChemSky #CompChemSky