Markus Bursch

Software Update: The ORCA Program System—Version 6.0 This article describes the philosophy behind- and new features in the ORCA quantum chemistry program suite, version 6.0.

Dear ORCA community,

it took a while, but now the ORCA 6.0 article is out! It serves as generic reference for ORCA 6.x. However, if you are serious about supporting our efforts, please take note of the suggested citations at the end of each ORCA run.

wires.onlinelibrary.wiley.com/doi/10.1002/...

The accessibility of state-of-the-art quantum chemistry is a core aspect of ORCA. We are therefore particularly proud that ORCA (@FACCTs & @orca-qc-official.bsky.social) is being used in such innovative projects as El Agente. Check it out!

#ORCAqc #CompChem #LLM #QuantumChem #ChemSky

Reposting for other time zones. In my latest video I show how to parameterize bond length and angle force constants in a semiautomatic fashion using the #orca #compoundscripts module.

I uploaded the files from the video to:
github.com/niconeuman/p...

Thank you for your outstanding pioneering work for the recognition of computational chemistry, Lisa! It was great to see how much heart and soul you put into this topic. It was an honor and great pleasure to co-author this article.

We wish you good luck and success on your new journey!

The “Bubblepole” (BUPO) Method for Linear-Scaling Coulomb Matrix Construction with or without Density Fitting In this work, we describe the development of a new algorithm for the computation of Coulomb-type matrices using the well-known resolution of the identity (RI) or density fitting (DF) approximation. The method is linear-scaling with respect to system size and computationally highly efficient. For small molecules, it performs almost as well as the Split-RI-J algorithm (which might be the most efficient RI-J implementation to date), while outperforming it for larger systems with about 300 or more atoms. The method achieves linear scaling through multipole approximations and a hierarchical treatment of multipoles. However, unlike in the fast multipole method (FMM), the algorithm does not use a hierarchical boxing algorithm. Rather, close-lying objects like auxiliary basis shells and basis set shell pairs are grouped together in spheres that enclose the set of objects completely, which includes a new definition of the shell-pair extent that defines a real-space radius outside of which a given shell pair can be safely assumed to be negligible. We refer to these spheres as “bubbles” and therefore refer to the algorithm as the “Bubblepole” (BUPO) algorithm, with the acronym being RI-BUPO-J. The bubbles are constructed in a way to contain a nearly constant number of objects such that a very even workload arises. The hierarchical bubble structure adapts itself to the molecular topology and geometry. For any target object (shell pair or auxiliary shell), one might envision that the bubbles “carve” out what might be referred to as a “far-field surface”. Using the default settings determined in this work, we demonstrate that the algorithm reaches submicro-Eh and even nano-Eh accuracy in the total Coulomb energy for systems as large as 700 atoms and 7000 basis functions. The largest calculations performed (the crambin protein solvated by 500 explicit water molecules in a triple-ζ basis) featured more than 2000 atoms and more than 33,000 basis functions.

This paper is the start of something big - a new way to use Multipoles in electronic structure calculations. We are extremely excited and proud that this is out now.

pubs.acs.org/doi/10.1021/...

Quick follow up to the paper: here is GOAT doing a conformational search of a ligand on a protein pocket, including a few waters. The protein was frozen but does not need to be.

All done in ORCA6 using QM/MM for the PES.

Have fun with it! 😀 #compchemsky 🧪

onlinelibrary.wiley.com/doi/abs/10.1...

GOAT: A Global Optimization Algorithm for Molecules and Atomic Clusters Bernardo de Souza (2025) Highlighted by Jan Jensen If you want to predict accurate reaction energies and barrier heights of typical organic ...

New CCH highlight: GOAT: A Global Optimization Algorithm for Molecules and Atomic Clusters
www.compchemhighlights.org/2025/02/goat... #compchem

The ORCA team is looking for a postdoctoral fellow or Ph.D. student to work on XTB methodology jointly with the group of Prof. Stefan Grimme (University of Bonn).

GOAT: A Global Optimization Algorithm for Molecules and Atomic Clusters In this work, we propose a new Global Optimization Algorithm (GOAT) for molecules and clusters of atoms and show how it can find the global energy minima for both systems without resorting to molecul...

The paper on ORCA 6’s Global Optimization Algorithm GOAT is finally published at Angewandte Chemie! Feel free to try Bernardo's (@bernadsz.bsky.social) algorithm to generate conformer ensembles and much more.

doi.org/10.1002/anie...

Tutorial on GOAT: www.faccts.de/docs/orca/6....

#ORCAqc #ChemSky

QCxMS2 - a program for the calculation of electron ion- ization mass spectra via automated reaction network dis- covery We present a new fully-automated computational workflow for the calculation of electron ionization mass spectra by automated reaction network discovery, transition state theory and Monte-Carlo simulat...

The quantum chemical prediction of EI-MS spectra is an important challenge. Check out @grimmelab.bsky.social's new preprint on their QCxMS2 program using ORCA's QM portfolio and NEB-TS infrastructure.

doi.org/10.26434/che...

#ORCAqc #ChemSky #CompChemSky #MassSpectrometry

YouTube video by nicolas N Fluorescence Spectra with Orca

New video on how to calculate #Fluorescence spectra with #Orca using the ESD module! I follow the example for benzene from the manual.

#compchem #chemsky #science

youtu.be/zWzPkqN9SBo

VWSCC 2025 - YouTube All recordings from the ORCA workshop at the Virtual Winter School on Computational Chemistry 2025.

All recordings of the ORCA workshop (@faccts-orca.bsky.social & @orca-qc-official.bsky.social) at the VWSCC 2025 (@vwscc.bsky.social) are now available on our YouTube Channel! Thank you to all participants who made it a great success.

www.youtube.com/playlist?lis...

#ORCAqc #ChemSky #VWSCC25

#ChemSky #QuantumChem

xTB Workshop VWSCC 2025 by the Grimme group.

Also don't forget the xTB workshop by our friends and close collaborators at the @grimmelab.bsky.social. It will start today 10:00 CET!

Join us at the free Virtual Winter School on Computational Chemistry and learn more about the features of ORCA 6! The ORCA workshop starts on Thursday, January 30th at 2 pm CET. The program and more information can be found here:

winterschool.cc/program/day-...

#ORCAqc #ORCA6 #VWSCC #ChemSky

Stefan Grimme receives the 2025 Chemistry Europe Award!
Learn more at https://buff.ly/3BXDVhO.

#ChemistryAward #ChemistryEurope

We're delighted to announce Stefan Grimme @grimmelab.bsky.social as the recipient of the 2025 Chemistry Europe Award! He'll be recognized "for his groundbreaking contributions that have had a profound impact on the scientific community” at #IUPAC2025.
www.chemistryviews.org/stefan-grimm...

#Chemsky

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 Release Event? No problem, all talks are now available on our YouTube channel (youtube.com/@faccts_orca), the academic (MPI Kofo) ORCA channel (youtube.com/@orcaquantum...), and the ORCA forum (orcaforum.kofo.mpg.de/app.php/portal).

#ORCAqc #ORCA6 #CompChem #QuantumChem #ChemSky

Save the date! We (@faccts-orca.bsky.social)will visit the 18th German Conference on Cheminformatics (GCC 2024, @gdch.bsky.social) in Bad Soden am Taunus, Germany from November 3rd to 6th. Visit us to find out more about us and our tools.

#GCC2024 #ORCA6 #CompChem #ChemInformatics #ChemSky

Solar Light CO2 Photoreduction Enhancement by Mononuclear Rhenium(I) Complexes: Characterization and Mechanistic Insights The catalytic efficacy of a novel mononuclear rhenium(I) complex in CO2 reduction is remarkable, with a turnover number (TONCO) of 1517 in 3 h, significantly outperforming previous Re(I) catalysts. Th...

ORCA offers a wide range of quantum chemical spectroscopy methods that can help solve complex chemical challenges. Learn more about them in our tutorials and our brand new online manual.

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

doi.org/10.1021/acs....

#ORCAqc #ChemSky

The first Quantum Mechanics in Pharma meeting starts today! Don't miss Christoph Riplinger’s (@faccts-orca.bsky.social) talk about "High-accuracy QM in life sciences: From drug properties to binding modes" at 15.40 (3:40 pm).

#ORCAqc #ORCA6 #CompChem #QuantumChem #PharmaChem #QMinPharma24 #ChemSky

YouTube video by nicolas N Global optimization using Orca6 and GOAT!

New video on using the GOAT method to find global minima with Orca and XTB, for a corrole dimer.
#compchem #chemsky
Pls help me share!

youtu.be/GvTNg2gKuZc

You want to get started with NMR predictions in ORCA? Check out our NMR tutorial at https//www.faccts....

1.3 Å Crystal Structure of E. coli Peptidyl–Prolyl Isomerase B with Uniform Substitution of Valine by (2S,3S)-4-Fluorovaline Reveals Structure Conservation and Multiple Staggered Rotamers of CH2F Groups (2S,3S)-4-Fluorovaline (FVal) is an analogue of valine, where a single CH3 group is substituted by a CH2F group. In the absence of valine, E. coli valyl-tRNA synthetase uses FVal as a substitute, enabling the production of proteins uniformly labeled with FVal. Here, we describe the production and analysis of E. coli peptidyl–prolyl isomerase B where all 16 valine residues have been replaced by FVal synthesized with a 13C-labeled CH2F group. Although the melting temperature is lower by about 11 °C relative to the wild-type protein, the three-dimensional protein structure is almost completely conserved, as shown by X-ray crystallography. The CH2F groups invariably populate staggered rotamers. Most CH2F groups populate two different rotamers. The increased space requirement of fluorine versus hydrogen does not prohibit rotamers that position fluorine next to a backbone carbonyl carbon. 19F NMR spectra show a signal dispersion over 25 ppm. The most high-field shifted 19F resonances correlate with large 3JHF coupling constants, confirming the impact of the γ-gauche effect on the signal dispersion. The present work is the second experimental verification of the effect and extends its validity to fluorovaline. The abundance of valine in proteins and structural conservation with FVal renders this valine analogue attractive for probing proteins by 19F NMR spectroscopy.

NMR properties are an important part of the spectroscopic toolbox of ORCA 6 (@faccts-orca.bsky.social & MPI Kofo). Jackson, Otting and coworkers recently used calculated 19F NMR properties to study structural effects in proteins.

doi.org/10.1021/acs....

#ORCAqc #ORCA6 #NMR #ChemSky #CompChem

Pushing the Limits of Organometallic Redox Chemistry with an Isolable Mn(−I) Dianion We report an incredibly reducing and redox-active Mn–I dianion, [Mn(CO)3(Ph2B(tBuNHC)2)]2– (NHC = N-heterocyclic carbene), furnished via 2e– reduction of the parent 16e– MnI complex with Na0 or K0. Cy...

If you want organometallic lightning in a bottle…. look no further⚡️⚡️⚡️We and isolated one of the strongest organometallic redox agents in existence. Even more reducing than naphthalenide! 🌶️🌶️🌶️
Congrats Ageliki, and thanks for the DFT collab @grimmelab.bsky.social !!

pubs.acs.org/doi/10.1021/...

Have you ever wanted to use your favorite double-hybrid #DFT method in a project, but the computational requirements were just too high? Check out our recent paper on DLPNO-DH-DFT, where we investigated how the DLPNO-MP2 approximation can help! #compchem
pubs.acs.org/doi/10.1021/...

Emerging Conformational-Analysis Protocols from the RTCONF55-16K Reaction Thermochemistry Conformational Benchmark Set RTCONF55-16K is a new, reactive conformational data set based on cost-efficient methods to assess different conformational analysis protocols. Our reference calculations underpinned the accuracy of th...

Large benchmark sets require an efficient QM software like ORCA (@FACCTs_ORCA & MPI Kofo) both to generate them and to test new methods. With ORCA 6, many tasks became even faster. Try it out, it's completely free for academic use!

#ORCAqc #ORCA6 #CompChem #ChemSky

pubs.acs.org/doi/10.1021/...

The spin-forbidden transition in iron(IV)-oxo catalysts relevant to two-state reactivity Resonant inelastic x-ray scattering reveals the triplet to quintet transition in iron(IV)-oxo complexes.

MCD and excited-state dynamics are only a small part of ORCA’s (FACCTs & MPI Kofo) spectroscopy toolkit. Check out the recent paper by Serena DeBeer, Frank Neese and co-workers on the spin-forbidden transition in iron(IV)-oxo catalysts.

doi.org/10.1126/scia...

#ORCAqc #CompChem #ChemSky

The 16th Latin American Conference on Physical Organic Chemistry (CLAFQO-16) starts on November 4th in Florianópolis, Brazil! Bernardo de Souza (@bernadsz.bsky.social) will give a presentation on the new Global Optimizer AlgoriThm (GOAT) in ORCA 6 (FACCTs & MPI Kofo).

#ORCAqc #ORCA6 #CLAFQO16

With ORCA 6 (FACCTs & MPI Kofo), openCOSMO-RS became part of its versatile solvation toolkit. Check out the new paper on its most recent parameterization (doi.org/10.1016/j.fl...) and try it yourself with our tutorial.

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

#ChemSky #ORCAqc #ORCA6 #Solvation #CompChem