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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 1901 November 22, 2024
CDFT Population Issues
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MRSF-TDDFT triplet-state calculation does not converge
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3 137 October 22, 2026
how to interpret Q-chem output file from Spartan26?
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1 104 October 21, 2026
Using Q-chem via Spartan26. Is it OK to post?
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1 103 October 20, 2026
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7 1748 October 20, 2026
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4 338 October 8, 2026
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1 176 October 5, 2026
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6 335 September 30, 2026
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1 294 September 28, 2026
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0 207 September 24, 2026
Q-Chem Webinar 90: Modeling materials with Q-Chem 7: overview of QCPBC and what's coming next
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0 286 September 22, 2026
Does BrianQC support CDFT-CI / legacy SCF engine in Q-Chem7?
Questions
1 266 September 16, 2026
Dyson orbitals between EOM-IP and EOM-DIP states with a CAP active
Questions
0 285 September 2, 2026
Frequency calculation stalls during CPSCF/CPCM-SWIG Hessian step
Questions
3 304 August 31, 2026
Spherical or Cartesian
Questions
4 331 August 26, 2026
r2scan very slow (not scf but doing extra calculations)
How To
1 303 August 20, 2026
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1 277 August 17, 2026
Q-Chem Webinar 89: M-Chem
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0 300 August 13, 2026
NAC rem variable error
Questions
1 347 August 5, 2026
ALMO_EDA job failure
Questions
3 877 August 10, 2026
BSSE error input file
Questions
5 908 August 10, 2026
Electron Coupling Calculation with CDFT and CDFT-CI approach
Questions
0 359 August 5, 2026
Webinar 88: What's new in Q-Chem 7
Announcements
0 362 July 28, 2026
CDFT-CI convergence issue
Questions
1 399 July 26, 2026
BOMD of two cationic fragments (coulomb explosion)
Questions
1 420 July 24, 2026
Help with incremental FCI (iFCI) example
Questions
1 1065 March 12, 2023
Some doubt regarding CAP onset
Questions
3 442 July 6, 2026
Calculation of transition density matrices between CVS-ADC(2)-x excited states
Questions
0 370 June 30, 2026
Unexpected Energy Ordering in TDDFT Nonequilibrium PCM
Questions
1 406 June 24, 2026