Q-Chem
@qchemsoftware.bsky.social
Q-Chem provides a comprehensive ab initio quantum chemistry program, allowing scientists worldwide to model chemical problems quickly and accurately.
http://q-chem.com/
http://q-chem.com/
2026 Nick Besley and Michael Wormit Award nominations are due this week! If you know someone who develops in Q-Chem or works with computational spectroscopy methods, please consider nominating them.
Wormit Award: q-chem.com/about/wormit/
Besley Award: q-chem.com/about/besley/
Wormit Award: q-chem.com/about/wormit/
Besley Award: q-chem.com/about/besley/
January 28, 2026 at 8:00 PM
2026 Nick Besley and Michael Wormit Award nominations are due this week! If you know someone who develops in Q-Chem or works with computational spectroscopy methods, please consider nominating them.
Wormit Award: q-chem.com/about/wormit/
Besley Award: q-chem.com/about/besley/
Wormit Award: q-chem.com/about/wormit/
Besley Award: q-chem.com/about/besley/
Don't forget about the 2026 Virtual Winter School in Computational Chemistry (VWSCC) meeting, happening next week! This is a great (free!) opportunity to learn and network, including talks and hands-on workshops! Learn more and register here: winterschool.cc #compchem
January 23, 2026 at 5:43 PM
Don't forget about the 2026 Virtual Winter School in Computational Chemistry (VWSCC) meeting, happening next week! This is a great (free!) opportunity to learn and network, including talks and hands-on workshops! Learn more and register here: winterschool.cc #compchem
Don't forget about the upcoming Q-Chem webinar from Avik Ojha; he will discuss his recent work implementing X-ray spectroscopy features in Q-Chem (including XCIS-CVS, which is now available now in Q-Chem 6.4)! Register here: zoom.us/webinar/regi...
January 21, 2026 at 9:23 PM
Don't forget about the upcoming Q-Chem webinar from Avik Ojha; he will discuss his recent work implementing X-ray spectroscopy features in Q-Chem (including XCIS-CVS, which is now available now in Q-Chem 6.4)! Register here: zoom.us/webinar/regi...
Don't miss next week's webinar from Q-Chem developer Avik Ojha (OSU), who will be talking about his recent CVS-XCIS implementation in Q-Chem for X-ray spectroscopy modeling. Read the abstract and register here: zoom.us/webinar/regi...
January 13, 2026 at 6:25 PM
Don't miss next week's webinar from Q-Chem developer Avik Ojha (OSU), who will be talking about his recent CVS-XCIS implementation in Q-Chem for X-ray spectroscopy modeling. Read the abstract and register here: zoom.us/webinar/regi...
Happy New Year! As we enter 2026, we want to celebrate the accomplishments of the Q-Chem community over the past year. Check out our 2025 Year In Review publications list: q-chem.com/news/2025-qc...
Thanks to all of our users and developers for making Q-Chem possible! ✨💫
Thanks to all of our users and developers for making Q-Chem possible! ✨💫
January 5, 2026 at 7:40 PM
Happy New Year! As we enter 2026, we want to celebrate the accomplishments of the Q-Chem community over the past year. Check out our 2025 Year In Review publications list: q-chem.com/news/2025-qc...
Thanks to all of our users and developers for making Q-Chem possible! ✨💫
Thanks to all of our users and developers for making Q-Chem possible! ✨💫
Q-Chem 6.4 includes Robust SCF: A simple black-box approach for improved convergence! It automatically detects and corrects common SCF convergence issues, including plateauing, oscillation, and unstable solutions. manual.q-chem.com/6.4/sub_scf_...
Try Q-Chem 6.4: q-chem.com/try/
Try Q-Chem 6.4: q-chem.com/try/
December 19, 2025 at 10:17 PM
Q-Chem 6.4 includes Robust SCF: A simple black-box approach for improved convergence! It automatically detects and corrects common SCF convergence issues, including plateauing, oscillation, and unstable solutions. manual.q-chem.com/6.4/sub_scf_...
Try Q-Chem 6.4: q-chem.com/try/
Try Q-Chem 6.4: q-chem.com/try/
In Q-Chem 6.4: Stochastic RI-CC2 analytical gradients and derivative coupling! Obtain accurate CC2 gradients faster, with O(N4) scaling with basis set size. Check out the recent preprint from developers:
doi.org/10.48550/arX...
Try Q-Chem 6.4: q-chem.com/try/
doi.org/10.48550/arX...
Try Q-Chem 6.4: q-chem.com/try/
December 17, 2025 at 9:30 PM
In Q-Chem 6.4: Stochastic RI-CC2 analytical gradients and derivative coupling! Obtain accurate CC2 gradients faster, with O(N4) scaling with basis set size. Check out the recent preprint from developers:
doi.org/10.48550/arX...
Try Q-Chem 6.4: q-chem.com/try/
doi.org/10.48550/arX...
Try Q-Chem 6.4: q-chem.com/try/
Q-Chem 6.4 includes new B97-type functionals for TAO-DFT! Read this paper from developers Shaozhi Li and Jeng-Da Chai, where they develop methods that perform well for both single- and multi-reference systems. doi.org/10.1021/acs....
Try Q-Chem 6.4 today: q-chem.com/try/
Try Q-Chem 6.4 today: q-chem.com/try/
December 16, 2025 at 6:56 PM
Q-Chem 6.4 includes new B97-type functionals for TAO-DFT! Read this paper from developers Shaozhi Li and Jeng-Da Chai, where they develop methods that perform well for both single- and multi-reference systems. doi.org/10.1021/acs....
Try Q-Chem 6.4 today: q-chem.com/try/
Try Q-Chem 6.4 today: q-chem.com/try/
New in Q-Chem 6.4: Iterative CC-in-DFT embedding! This new approach, developed by Anthuan Ferino Pérez and Thomas Jagau, provides high accuracy for relevant properties at lower cost. Read their paper to learn more: doi.org/10.1021/acs....
Try Q-Chem 6.4: q-chem.com/try/
Try Q-Chem 6.4: q-chem.com/try/
December 10, 2025 at 6:26 PM
New in Q-Chem 6.4: Iterative CC-in-DFT embedding! This new approach, developed by Anthuan Ferino Pérez and Thomas Jagau, provides high accuracy for relevant properties at lower cost. Read their paper to learn more: doi.org/10.1021/acs....
Try Q-Chem 6.4: q-chem.com/try/
Try Q-Chem 6.4: q-chem.com/try/
New in Q-Chem 6.4: Faster coupled cluster calculations! Our new two-step Cholesky decomposition for CC and EOM-CC energy and gradient (developed by Tingting Zhao and Anna Krylov) provides speedup. Learn more about features in our new release: q-chem.com/explore/qc64/
December 9, 2025 at 8:46 PM
New in Q-Chem 6.4: Faster coupled cluster calculations! Our new two-step Cholesky decomposition for CC and EOM-CC energy and gradient (developed by Tingting Zhao and Anna Krylov) provides speedup. Learn more about features in our new release: q-chem.com/explore/qc64/
Q-Chem 6.4 is here! Upgrade for new spectroscopy features (such as CVS-XCIS our new-and-improved ΔSCF driver), iterative CC-in-DFT embedding, faster CC calculations, MR-SF-DFT, stochastic RI-CC2, NEO methods, and more: q-chem.com/explore/qc64/
December 8, 2025 at 11:20 PM
Q-Chem 6.4 is here! Upgrade for new spectroscopy features (such as CVS-XCIS our new-and-improved ΔSCF driver), iterative CC-in-DFT embedding, faster CC calculations, MR-SF-DFT, stochastic RI-CC2, NEO methods, and more: q-chem.com/explore/qc64/
New in Q-Chem 6.4: XCIS-CVS! In a new paper, researchers use XCIS-CVS to accurately calculate core-level spectra for open-shell molecules, including transition metal complexes. doi.org/10.1021/acs....
CVS for ROCIS, CIS, and QROCIS is available in Q-Chem 6.4, coming next week!
CVS for ROCIS, CIS, and QROCIS is available in Q-Chem 6.4, coming next week!
December 5, 2025 at 9:51 PM
New in Q-Chem 6.4: XCIS-CVS! In a new paper, researchers use XCIS-CVS to accurately calculate core-level spectra for open-shell molecules, including transition metal complexes. doi.org/10.1021/acs....
CVS for ROCIS, CIS, and QROCIS is available in Q-Chem 6.4, coming next week!
CVS for ROCIS, CIS, and QROCIS is available in Q-Chem 6.4, coming next week!
New in Q-Chem 6.4: Improved ΔSCF! The input for ΔSCF is now one simple, easy-to-use section, making it easier to run than ever. The new ΔSCF driver (developed by Juanes Arias-Martinez) includes several other useful functionalities.
Q-Chem 6.4 is coming next week. Stay tuned!
Q-Chem 6.4 is coming next week. Stay tuned!
December 4, 2025 at 10:48 PM
New in Q-Chem 6.4: Improved ΔSCF! The input for ΔSCF is now one simple, easy-to-use section, making it easier to run than ever. The new ΔSCF driver (developed by Juanes Arias-Martinez) includes several other useful functionalities.
Q-Chem 6.4 is coming next week. Stay tuned!
Q-Chem 6.4 is coming next week. Stay tuned!
Check out this new paper: Authors use Q-Chem's EA-TDDFT and ALMO-EDA-PCM to uncover evidence pointing to the presence of interanionic hydrogen bonding (IAHB) in concentrated phosphoric acid solutions. pubs.acs.org/doi/10.1021/...
Try Q-Chem for free: q-chem.com/try/
Try Q-Chem for free: q-chem.com/try/
November 29, 2025 at 3:30 PM
Check out this new paper: Authors use Q-Chem's EA-TDDFT and ALMO-EDA-PCM to uncover evidence pointing to the presence of interanionic hydrogen bonding (IAHB) in concentrated phosphoric acid solutions. pubs.acs.org/doi/10.1021/...
Try Q-Chem for free: q-chem.com/try/
Try Q-Chem for free: q-chem.com/try/
Check out this recent preprint from Q-Chem developers at KU Leuven, who use EA-EOM-RICC2 in Q-Chem to study the reduction of ubiquinone (CoQ), a key step in cellular respiration. doi.org/10.26434/che...
Interested in becoming a Q-Chem developer? Learn more here: www.q-chem.com/about/team/d...
Interested in becoming a Q-Chem developer? Learn more here: www.q-chem.com/about/team/d...
November 20, 2025 at 7:15 PM
Check out this recent preprint from Q-Chem developers at KU Leuven, who use EA-EOM-RICC2 in Q-Chem to study the reduction of ubiquinone (CoQ), a key step in cellular respiration. doi.org/10.26434/che...
Interested in becoming a Q-Chem developer? Learn more here: www.q-chem.com/about/team/d...
Interested in becoming a Q-Chem developer? Learn more here: www.q-chem.com/about/team/d...
Don't miss tomorrow's webinar from Manisha on coupled cluster triples! If you can't make it at the scheduled time, still be sure to register—the webinar recording will be made available afterwards. zoom.us/webinar/regi...
November 18, 2025 at 10:16 PM
Don't miss tomorrow's webinar from Manisha on coupled cluster triples! If you can't make it at the scheduled time, still be sure to register—the webinar recording will be made available afterwards. zoom.us/webinar/regi...
Join us on 11/19 at 9PM PST for a webinar from Manisha, one of our 2025 Summer at Q-Chem interns! She will discuss her recent work with coupled cluster, including her recent Q-Chem implementations of CCSDt and several EOM-CCSDT variants. Register here: zoom.us/webinar/regi...
November 14, 2025 at 8:40 PM
Join us on 11/19 at 9PM PST for a webinar from Manisha, one of our 2025 Summer at Q-Chem interns! She will discuss her recent work with coupled cluster, including her recent Q-Chem implementations of CCSDt and several EOM-CCSDT variants. Register here: zoom.us/webinar/regi...
In this recent preprint, researchers use Q-Chem to help design and characterize a merocyanine metastable-state photoacid! They use the proposed monomer to build a series of light-responsive polymers. doi.org/10.26434/che...
Try Q-Chem today: q-chem.com/try/
Try Q-Chem today: q-chem.com/try/
November 12, 2025 at 11:11 PM
In this recent preprint, researchers use Q-Chem to help design and characterize a merocyanine metastable-state photoacid! They use the proposed monomer to build a series of light-responsive polymers. doi.org/10.26434/che...
Try Q-Chem today: q-chem.com/try/
Try Q-Chem today: q-chem.com/try/
In this preprint, Q-Chem developers introduce two implementations of sRI-CC2 for excited-state analytical gradients and derivative couplings. Their partial sRI-CC2 method, available in Q-Chem 6.4, is significantly faster than traditional RI-CC2 approaches! doi.org/10.48550/arX...
November 7, 2025 at 6:58 PM
In this preprint, Q-Chem developers introduce two implementations of sRI-CC2 for excited-state analytical gradients and derivative couplings. Their partial sRI-CC2 method, available in Q-Chem 6.4, is significantly faster than traditional RI-CC2 approaches! doi.org/10.48550/arX...
In this recent preprint, Q-Chem developers introduce a new method for modeling the XAS of open-shell systems! Their approach, included in the upcoming Q-Chem 6.4 release, yields semi-quantitative K-edge and pre-edge orbital splittings. doi.org/10.26434/che...
November 5, 2025 at 10:11 PM
In this recent preprint, Q-Chem developers introduce a new method for modeling the XAS of open-shell systems! Their approach, included in the upcoming Q-Chem 6.4 release, yields semi-quantitative K-edge and pre-edge orbital splittings. doi.org/10.26434/che...
Join us for an upcoming Q-Chem webinar on November 19th from Manisha, one of our Summer At Q-Chem interns! She will be discussing her work with coupled cluster methods in Q-Chem. Read the abstract and register here: zoom.us/webinar/regi...
November 4, 2025 at 9:36 PM
Join us for an upcoming Q-Chem webinar on November 19th from Manisha, one of our Summer At Q-Chem interns! She will be discussing her work with coupled cluster methods in Q-Chem. Read the abstract and register here: zoom.us/webinar/regi...
In this preprint, authors examine the discrepancy between experimental and theoretical results based on Marcus theory for C-13-ae, using a new scheme (E-SHAKE) to sample the seam between two diabatic electronic states. arxiv.org/pdf/2510.11810
Try Q-Chem: q-chem.com/try/
Try Q-Chem: q-chem.com/try/
November 1, 2025 at 8:33 PM
In this preprint, authors examine the discrepancy between experimental and theoretical results based on Marcus theory for C-13-ae, using a new scheme (E-SHAKE) to sample the seam between two diabatic electronic states. arxiv.org/pdf/2510.11810
Try Q-Chem: q-chem.com/try/
Try Q-Chem: q-chem.com/try/
Researchers accurately model the UV absorption spectrum of the hydroxyl anion in water. They use Q-Chem's CCSD and EOM-CCSD to run highly-accurate QM simulations on clusters generated via MD: doi.org/10.1016/j.mo...
Try Q-Chem today: q-chem.com/try/
Try Q-Chem today: q-chem.com/try/
October 29, 2025 at 8:19 PM
Researchers accurately model the UV absorption spectrum of the hydroxyl anion in water. They use Q-Chem's CCSD and EOM-CCSD to run highly-accurate QM simulations on clusters generated via MD: doi.org/10.1016/j.mo...
Try Q-Chem today: q-chem.com/try/
Try Q-Chem today: q-chem.com/try/
In this recent paper, authors use penalty-constrained geometry optimization and SF-LC-TDDFT in Q-Chem 6.3 to study the fluorescence quenching mechanism of a styrene derivative at a conical intersection: doi.org/10.1021/acso...
Try Q-Chem 6.3 today: q-chem.com/try/
Try Q-Chem 6.3 today: q-chem.com/try/
October 28, 2025 at 8:38 PM
In this recent paper, authors use penalty-constrained geometry optimization and SF-LC-TDDFT in Q-Chem 6.3 to study the fluorescence quenching mechanism of a styrene derivative at a conical intersection: doi.org/10.1021/acso...
Try Q-Chem 6.3 today: q-chem.com/try/
Try Q-Chem 6.3 today: q-chem.com/try/
Can energy decomposition analysis (EDA) be used for excited states? In this recent preprint, Q-Chem developers present an approach for using EDA with ROKS, which is used for single-electron excitations. doi.org/10.26434/che...
Try Q-Chem: q-chem.com/try/
Try Q-Chem: q-chem.com/try/
October 21, 2025 at 10:36 PM
Can energy decomposition analysis (EDA) be used for excited states? In this recent preprint, Q-Chem developers present an approach for using EDA with ROKS, which is used for single-electron excitations. doi.org/10.26434/che...
Try Q-Chem: q-chem.com/try/
Try Q-Chem: q-chem.com/try/