FACCTs
@faccts.de
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FACCTs is bringing the ORCA quantum chemistry software to industry - promoting the next Quantum leaps in the Pharma, Materials and Chemical Industries. Visit us at www.faccts.de
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FACCTs @faccts.de · Jun 23
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
GitHub - faccts/opi: ORCA Python Interface
ORCA Python Interface. Contribute to faccts/opi development by creating an account on GitHub.
github.com
faccts.de
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!

#FACCTs #ORCAqc #SMASH2025 #CompChem #TheoChem #NMR
FACCTs at the SMASH 2025
faccts.de
We 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!

#FACCTs #ORCAqc #STC2025 #CompChem #TheoChem
FACCTs at the STC 2025
Reposted by FACCTs
llangresearch.bsky.social
I have an open PhD position. The exact topic is negotiable and can range from implementing new quantum-chemical methods in @orca-qc-official.bsky.social to computational studies of open-shell molecules.
🔗 Details: www.langresearch.org/open-phd-fel...

Please share!

#PhDposition #CompChem
Open PhD Fellowship in Quantum Chemistry at TU Berlin – Lang Research Group
www.langresearch.org
Reposted by FACCTs
avogadro.cc
We've got a new release 1.101, which should particularly fix some bugs with Windows and Mac, and of course a variety of new features.

Highlights include support for constraints for geometry optimizations, tweaking bond lengths when changing elements, and more...

discuss.avogadro.cc/t/avogadro-1...
faccts.de
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
FACCTs at EuChemS CompChem 2025
faccts.de
Check out the latest release of QCxMS2 by @jogorges.bsky.social (@grimmelab.bsky.social) introducing CID. Thank you, Johannes, for interfacing it with ORCA as a QM engine!

#ORCAqc #ORCA6 #massspectrometry #CID #CompChem #ChemSky #CompChemSky
jogorges.bsky.social
QCxMS2 can now also simulate CID mass spectra.

Just published in #JASMS : doi.org/10.1021/jasms.5c00234

Grateful to my coauthors Stefan Grimme @grimmelab.bsky.social & Marianne Engeser @unibonn.bsky.social - this is the last project of my PhD and completes my work on QCxMS2!

#MassSpec #compchem
Evaluation of the QCxMS2 Method for the Calculation of Collision-Induced Dissociation Spectra via Automated Reaction Network Exploration
Collision-induced dissociation mass spectrometry (CID-MS) is an important tool in analytical chemistry for the structural elucidation of unknown compounds. The theoretical prediction of the CID spectra plays a critical role in supporting and accelerating this process. To this end, we adapt the recently developed QCxMS2 program originally designed for the calculation of electron ionization (EI) spectra to enable the computation of CID-MS. To account for the fragmentation conditions characteristic of CID within the automated reaction network discovery approach of QCxMS2 we adapted the internal energy distribution to match the experimental conditions. This distribution can be adjusted via a single parameter to approximate various activation settings, thereby eliminating the need for explicit simulations of the collisional process. We evaluate our approach on a test set of 13 organic molecules with diverse functional groups, compiled specifically for this study. All reference spectra were recorded consistently under the same measurement conditions, including both CID and higher-energy collisional dissociation (HCD) modes. Overall, QCxMS2 achieves a good average entropy similarity score (ESS) of 0.687 for the HCD spectra and 0.773 for the CID spectra. The direct comparison to experimental data demonstrates that the QCxMS2 approach, even without explicit modeling of collisions, is generally capable of computing both CID and HCD spectra with reasonable accuracy and robustness. This highlights its potential as a valuable tool for integration into structure elucidation workflows in analytical mass spectrometry.
doi.org
Reposted by FACCTs
grimmelab.bsky.social
🚀 JCIM: "Chemical Space Exploration with Artificial Mindless Molecules"

We present MindlessGen, an open-source tool for generating chemically diverse "mindless" molecules, and the MB2061 benchmark set with high-level reference data to test methods on unconventional systems.

doi.org/10.1021/acs....
Chemical Space Exploration with Artificial “Mindless” Molecules
We introduce MindlessGen, a Python-based generator for creating chemically diverse, “mindless” molecules through random atomic placement and subsequent geometry optimization. Using this framework, we ...
doi.org
faccts.de
FACCTs @faccts.de · Aug 27
Great to see many of our collaborators and friends from the ORCA community including Michael Römelt, Dimitrios Pantazis, @podewitzlab.bsky.social, @letigonzalez.bsky.social, @kulikgroup.bsky.social, and many more at the QBIC VII in Berlin, Germany!

#QBICVII #CompChemSky #ChemSky #ORCAqc #ORCA
QBIC VII in Berlin sponsored by FACCTs
faccts.de
FACCTs @faccts.de · Aug 26
#ChemSky #CompChemSky
faccts.de
FACCTs @faccts.de · Aug 26
#ChemSky #CompChemSky
faccts.de
FACCTs @faccts.de · Aug 25
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
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.
doi.org
faccts.de
FACCTs @faccts.de · Aug 16
Thankyou very much, any feedback on how to improve OPI is welcome!
faccts.de
FACCTs @faccts.de · Aug 8
Congratulations Tim!
Reposted by FACCTs
olexandr.bsky.social
Most of MLIPs dont distinguish between spin states, making them unsuitable for open-shell chemistry. We present AIMNet2-NSE (Neural Spin-charge Equilibration), MLIP that incorporates spin-charge equilibration for systems with arbitrary charge and spin. #compchem #skychem
chemrxiv.org/engage/chemr...
faccts.de
FACCTs @faccts.de · Jul 28
Check out our most recent collaboration on atomic polarizabilities calculated with ORCA and how they can be used to improve openCOSMO-RS.

doi.org/10.1016/j.ce...

Calculation of atomic polarizabilities with ORCA 6.1:

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

#ORCAqc #Solvation #CompChem #openCOSMORS
Redirecting
doi.org
Reposted by FACCTs
grynova.bsky.social
In this week’s #JournalClub @jeanquertinmont.bsky.social discusses resolution of identity / density fitting approaches #compchem with a special focus on @orca-qc-official.bsky.social www.grynova-ccc.org/journal-club...
faccts.de
FACCTs @faccts.de · Jul 3
We are also very excited about g-xTB @grimmelab.bsky.social ! You can also try it with ORCA via the ExtOpt feature for GOAT, NEB-TS etc.!

www.faccts.de/docs/orca/6....
ORCA as External Optimizer - ORCA 6.1 TUTORIALS
www.faccts.de
faccts.de
FACCTs @faccts.de · Jun 26
Mainly the new COVALED method (available in ORCA6.1: www.faccts.de/docs/orca/6....) was discussed. The corresponding manuscript is currently in preparation.
5.38. Local Energy Decomposition - ORCA 6.1 Manual
www.faccts.de
faccts.de
FACCTs @faccts.de · Jun 26
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
ORCA as External Optimizer - ORCA 6.1 TUTORIALS
www.faccts.de
faccts.de
FACCTs @faccts.de · Jun 25
Thank you very much! We hope you're having fun with OPI and any feedback/contribution is welcome.