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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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Cannot get rid of Imaginary Frequency
Questions
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TDA with RSH giving negative triplet excitation
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6 113 November 19, 2025
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Questions
11 519 November 11, 2025
“double free or corruption (out)” error in TDDFT + EFP job with large number of fragments
Questions
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Cannot escape an imaginary frequency
Questions
1 166 November 7, 2025
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TSVDW and MBD crashes
Questions
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Unexpected behaviour: core orbitals are not frozen during MP2/MP3 step in ADC calculations
Questions
4 305 October 27, 2025
SCF convergence issue with diffuse functions on basis set
Questions
27 555 October 22, 2025
Crash upon frequency calculations with range separated bybrid
Questions
1 245 October 21, 2025
Cryptic import_xcfunc warning
Questions
10 381 October 20, 2025