Topic Replies Views Activity
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 1377 November 22, 2024
Non-adiabatic bimolecular reaction dynamics
Questions
3 74 April 17, 2026
Energy inconsistency with PySCF / adcc
Questions
3 40 April 17, 2026
Facing Imaginary frequency in excited state
Questions
1 25 April 17, 2026
Issue with fragment job submission in Q-Chem 5.0.1 EDA calculations
Questions
3 56 April 13, 2026
Crash with NO_REORIENT
Questions
4 83 April 10, 2026
Facing large number of imaginary frequencies in LRC-wPBE functional
Questions
3 72 April 7, 2026
Error in RI-EA-CC2 calculation
Questions
3 90 April 5, 2026
Issue with BR89
Questions
3 79 April 2, 2026
IRC calculation issue
Questions
2 113 April 1, 2026
NAC calculation
Questions
3 144 March 27, 2026
How to generate FCIDump file
Questions
3 104 March 25, 2026
SCF convergence problem in CDFT-CI calculation
Questions
3 129 March 24, 2026
Strange outcome in RAS-SF calculation
Questions
0 93 March 17, 2026
Speeding up ADC(2) calculations
Questions
2 137 March 17, 2026
Is it possible to print gradients of several excited states?
Questions
3 129 March 14, 2026
Memory and RICIS(D) calculations
Questions
4 120 March 11, 2026
MRSF: differences between Q-Chem and OpenQP
Questions
0 150 March 8, 2026
SOC for unrestricted TDDFT
Questions
3 378 March 6, 2026
Gradient and Hessian using CCSD and EOM-CCSD
Questions
3 147 March 5, 2026
Resolution of identity for CDFT?
Questions
6 180 March 3, 2026
ROHF energy discrepancy between Q-Chem and CFOUR
Questions
4 200 February 28, 2026
Optimal settings for large DFT calculations
Questions
3 536 February 28, 2026
Using FRAGMO with ptSS-PCM and CDFT for Vertical Electron Transfer Calculation
Questions
3 142 February 26, 2026
Geometry Optimization with SS_PCM
Questions
1 172 February 25, 2026
Thresh/s2thresh 14?
Questions
8 196 February 24, 2026
Normal Modes Question
Questions
3 354 February 23, 2026
Symmetry in CCSD(T) frequency calculation
Questions
4 207 February 23, 2026
Symmetry of EOM-EA-CCSD. Significance?
Questions
1 190 February 21, 2026
Units of vibrational eigenvectors
Questions
2 232 February 20, 2026