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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 1711 November 22, 2024
Frequency calculation stalls during CPSCF/CPCM-SWIG Hessian step
Questions
1 23 August 29, 2026
Spherical or Cartesian
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4 63 August 26, 2026
r2scan very slow (not scf but doing extra calculations)
How To
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Q-Chem Webinar 89: M-Chem
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BSSE error input file
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0 130 August 5, 2026
Webinar 88: What's new in Q-Chem 7
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CDFT-CI convergence issue
Questions
1 182 July 26, 2026
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Questions
1 204 July 24, 2026
Help with incremental FCI (iFCI) example
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1 917 March 12, 2023
Some doubt regarding CAP onset
Questions
3 229 July 6, 2026
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Questions
0 198 June 30, 2026
Unexpected Energy Ordering in TDDFT Nonequilibrium PCM
Questions
1 225 June 24, 2026
Amber force field generation
Questions
3 303 June 23, 2026
What sort of SCF calculations are supported with external fields?
Questions
5 317 June 16, 2026
CDFT-CI Coupling convergence issue
Questions
5 319 June 15, 2026
ALMO-EDA/COVP SCF Convergence Failure for Open-Shell Anion Radical System
Questions
6 420 June 13, 2026
Lowering amplitude threshold when doing eom CCSD job
Questions
0 229 June 11, 2026
Error in RI-EA-CC2 calculation
Questions
4 493 June 7, 2026
FCIDUMP support
Questions
1 260 June 5, 2026
Upgrade to DFT-D4 in QChem 6.4
Questions
1 293 June 4, 2026
Electronic structures of TDDFT-1D states
Questions
0 274 June 2, 2026
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Questions
1 294 May 29, 2026
Simulating Vibronic and Resonance Raman Spectroscopy Using the VIBRONIC module of Q-Chem
How To
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Questions
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Restarting finite difference frequency jobs
Questions
4 1827 May 18, 2026