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Report SCF (HF/DFT) Convergence Issues
Questions

Dear Q-Chem Community, If you have any SCF (HF/DFT) jobs that are time-consuming or are facing convergence difficulties with Q-Chem, please send them to support@q-chem.com with the subject line “SCF Convergence Issue” t…

3 1502 November 22, 2024
Lowering amplitude threshold when doing eom CCSD job
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0 9 June 11, 2026
Error in RI-EA-CC2 calculation
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4 274 June 7, 2026
FCIDUMP support
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1 52 June 5, 2026
ALMO-EDA/COVP SCF Convergence Failure for Open-Shell Anion Radical System
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5 86 June 5, 2026
Upgrade to DFT-D4 in QChem 6.4
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1 62 June 4, 2026
Electronic structures of TDDFT-1D states
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0 69 June 2, 2026
Challenges in CDFT Geometry Optimization Using aug-cc-pVDZ
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1 77 May 29, 2026
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How To
18 4119 May 25, 2026
QM/EFP Setup in Q-Chem with Ghost Atoms Only (Excess Electron in Cavity)
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1 101 May 22, 2026
Restarting finite difference frequency jobs
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4 1630 May 18, 2026
“ADC(3) singlet and triplet excited states with PCM – input and disk quota issues”
Questions
4 565 May 18, 2026
aug-cc-pV5Z with external charges
Questions
3 184 May 13, 2026
CDFT block set up
How To
1 143 May 7, 2026
New basis set - excited states of Argon
Questions
3 203 May 5, 2026
PES scan not respecting mem_total
Questions
6 178 May 4, 2026
How to use SGM method to calculate triplet excited states with ROKS?
Questions
3 201 May 3, 2026
Improving the accuracy of CPHF
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1 154 May 1, 2026
TDDFT SOC results
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3 264 April 28, 2026
Failure in Frequency job
Questions
3 191 April 24, 2026
Webinar 87: Improvements in the OO-DFT user interface
Webinars
0 174 April 23, 2026
Facing convergence issue with CDFT geometry optimization
Questions
1 176 April 22, 2026
Loading basis set from file?
Questions
1 178 April 22, 2026
Non-adiabatic bimolecular reaction dynamics
Questions
5 281 April 18, 2026
Energy inconsistency with PySCF / adcc
Questions
3 272 April 17, 2026
Facing Imaginary frequency in excited state
Questions
1 199 April 17, 2026
Issue with fragment job submission in Q-Chem 5.0.1 EDA calculations
Questions
3 217 April 13, 2026
Crash with NO_REORIENT
Questions
4 240 April 10, 2026
Facing large number of imaginary frequencies in LRC-wPBE functional
Questions
3 228 April 7, 2026
Issue with BR89
Questions
3 252 April 2, 2026