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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…

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Thresh/s2thresh 14?
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Normal Modes Question
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Symmetry in CCSD(T) frequency calculation
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EOM-EA-CCSD on a Excited state
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0 33 February 20, 2026
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1 41 February 20, 2026
Frequency calculation speedup
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1 52 February 19, 2026
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2 66 February 19, 2026
Large number of imaginary frequencies with ROKS and delta SCF
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1 43 February 19, 2026
Ehrenfest Molecular Dynamics
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2 46 February 19, 2026
S1 Geom optimization based on TDDFT and delta SCF approach
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11 133 February 18, 2026
Q-Chem license on new MacOS
How To
0 49 February 17, 2026
Stuck CCSD frequency calculation
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2 84 February 16, 2026
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4 57 February 15, 2026
COSMO input file
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2 65 February 13, 2026
VQCCD single point calculation issue
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0 55 February 13, 2026
RIXS with TDDFT
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0 59 February 12, 2026
Wrong multiplicity for large multiplicity element when using projection based embedding
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3 67 February 12, 2026
Ground state out of equilibrium calculation
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3 125 February 11, 2026
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8 266 February 9, 2026
CASSCF with Nonadiabatic Coupling
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1 80 February 6, 2026
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3 106 February 6, 2026
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3 115 February 2, 2026
SOC for unrestricted TDDFT
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2 140 January 30, 2026
Visualization/export of SF-TDDFT orbitals
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5 188 January 27, 2026
Error while running frequency calculation
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4 127 January 27, 2026
Frozen atoms move during optimization
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2 133 January 27, 2026