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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 1123 November 22, 2024
Is it possible to use the NTO-rotated orbitals (for a specific TDDFT state) as the MO set in a subsequent Q-Chem job?
Questions
2 27 December 29, 2025
Gradient/Force print in cartesian format for each element
Questions
1 24 December 28, 2025
License file for 32 cores in a 128 cores computing node
Questions
1 33 December 24, 2025
Checking the input file for inconsistencies... Error Debug
Questions
3 54 December 23, 2025
Basis set compatibility issue
Questions
3 76 December 23, 2025
IEF-PCM for SMD olvation model
Questions
1 59 December 18, 2025
Possible issue with linear dependencies in the basis when calculating dynamic polarizabilities
Questions
5 93 December 18, 2025
downloading and installing qcIntel version 6402
Questions
1 69 December 17, 2025
Discrepancies between RIMP2 polarizabilities with FDIF = 0 and FDIF = 1
Questions
1 69 December 12, 2025
Excitation energy transfer between two carotinoids
Questions
3 85 December 12, 2025
Machine learned PES
Questions
1 120 December 1, 2025
Partial frozen scan
Questions
3 128 November 29, 2025
Dipole Moments with MBD dispersion
Questions
1 103 November 28, 2025
Correlation consistent basis sets and effective core potentials should be included?
Questions
1 156 November 28, 2025
vdW-TS (MBDVDW) vibrational frequencies
Questions
15 179 November 27, 2025
neo-scf calculations
Questions
1 88 November 25, 2025
aug-cc-pV(n+d)Z basis sets
Questions
1 97 November 25, 2025
Cannot get rid of Imaginary Frequency
Questions
3 157 November 25, 2025
TDA with RSH giving negative triplet excitation
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11 199 November 24, 2025
“ADC(3) singlet and triplet excited states with PCM – input and disk quota issues”
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3 374 November 21, 2025
Second Derivative for DC-DFT
How To
9 348 November 21, 2025
TD-DFT geometry optimization using IEFPCM solvation model
Questions
1 130 November 20, 2025
Webinar 83: Coupled Cluster Developments in Q-Chem
Webinars
0 113 November 20, 2025
Obtaining cube file for mo's, suggesting bond breaking
Questions
2 109 November 19, 2025
Trouble using EOM-CCSD, with frozen core
Questions
6 150 November 19, 2025
Issue with S₁ State Optimization Under PCM – SCF Convergence Error
Questions
3 141 November 18, 2025
How to set broken‑symmetry state?
Questions
7 171 November 17, 2025
Problem oxygen potential energy scan using CCSD(T) and EA state PES using EA-EOM-CCSD
Questions
11 564 November 11, 2025
“double free or corruption (out)” error in TDDFT + EFP job with large number of fragments
Questions
1 152 November 9, 2025