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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 1707 November 22, 2024
Frequency calculation stalls during CPSCF/CPCM-SWIG Hessian step
Questions
0 13 August 28, 2026
Spherical or Cartesian
Questions
4 58 August 26, 2026
r2scan very slow (not scf but doing extra calculations)
How To
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1 74 August 17, 2026
Q-Chem Webinar 89: M-Chem
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NAC rem variable error
Questions
1 139 August 5, 2026
ALMO_EDA job failure
Questions
3 631 August 10, 2026
BSSE error input file
Questions
5 691 August 10, 2026
Electron Coupling Calculation with CDFT and CDFT-CI approach
Questions
0 128 August 5, 2026
Webinar 88: What's new in Q-Chem 7
Announcements
0 158 July 28, 2026
CDFT-CI convergence issue
Questions
1 178 July 26, 2026
BOMD of two cationic fragments (coulomb explosion)
Questions
1 201 July 24, 2026
Help with incremental FCI (iFCI) example
Questions
1 914 March 12, 2023
Some doubt regarding CAP onset
Questions
3 222 July 6, 2026
Calculation of transition density matrices between CVS-ADC(2)-x excited states
Questions
0 197 June 30, 2026
Unexpected Energy Ordering in TDDFT Nonequilibrium PCM
Questions
1 223 June 24, 2026
Amber force field generation
Questions
3 301 June 23, 2026
What sort of SCF calculations are supported with external fields?
Questions
5 315 June 16, 2026
CDFT-CI Coupling convergence issue
Questions
5 315 June 15, 2026
ALMO-EDA/COVP SCF Convergence Failure for Open-Shell Anion Radical System
Questions
6 417 June 13, 2026
Lowering amplitude threshold when doing eom CCSD job
Questions
0 226 June 11, 2026
Error in RI-EA-CC2 calculation
Questions
4 489 June 7, 2026
FCIDUMP support
Questions
1 257 June 5, 2026
Upgrade to DFT-D4 in QChem 6.4
Questions
1 287 June 4, 2026
Electronic structures of TDDFT-1D states
Questions
0 271 June 2, 2026
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Questions
1 292 May 29, 2026
Simulating Vibronic and Resonance Raman Spectroscopy Using the VIBRONIC module of Q-Chem
How To
18 4722 May 25, 2026
QM/EFP Setup in Q-Chem with Ghost Atoms Only (Excess Electron in Cavity)
Questions
1 1814 May 22, 2026
Restarting finite difference frequency jobs
Questions
4 1825 May 18, 2026