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 1356 November 22, 2024
Error in RI-EA-CC2 calculation
Questions
1 12 April 4, 2026
Issue with BR89
Questions
3 49 April 2, 2026
IRC calculation issue
Questions
2 73 April 1, 2026
NAC calculation
Questions
3 106 March 27, 2026
How to generate FCIDump file
Questions
3 76 March 25, 2026
SCF convergence problem in CDFT-CI calculation
Questions
3 105 March 24, 2026
Strange outcome in RAS-SF calculation
Questions
0 71 March 17, 2026
Speeding up ADC(2) calculations
Questions
2 101 March 17, 2026
Is it possible to print gradients of several excited states?
Questions
3 112 March 14, 2026
Memory and RICIS(D) calculations
Questions
4 98 March 11, 2026
MRSF: differences between Q-Chem and OpenQP
Questions
0 123 March 8, 2026
SOC for unrestricted TDDFT
Questions
3 333 March 6, 2026
Gradient and Hessian using CCSD and EOM-CCSD
Questions
3 122 March 5, 2026
Resolution of identity for CDFT?
Questions
6 151 March 3, 2026
ROHF energy discrepancy between Q-Chem and CFOUR
Questions
4 173 February 28, 2026
Optimal settings for large DFT calculations
Questions
3 516 February 28, 2026
Using FRAGMO with ptSS-PCM and CDFT for Vertical Electron Transfer Calculation
Questions
3 123 February 26, 2026
Geometry Optimization with SS_PCM
Questions
1 145 February 25, 2026
Thresh/s2thresh 14?
Questions
8 171 February 24, 2026
Normal Modes Question
Questions
3 317 February 23, 2026
Symmetry in CCSD(T) frequency calculation
Questions
4 175 February 23, 2026
Symmetry of EOM-EA-CCSD. Significance?
Questions
1 171 February 21, 2026
Units of vibrational eigenvectors
Questions
2 214 February 20, 2026
EOM-EA-CCSD on a Excited state
Questions
1 143 February 20, 2026
ROKS emission energy with nonequilibrium solvent
Questions
0 134 February 20, 2026
Dyson orbital using EOMCCSDT-IP
Questions
1 169 February 20, 2026
Frequency calculation speedup
Questions
1 301 February 19, 2026
What is the correct input for the GEOM_OPT_MODE
Questions
2 184 February 19, 2026
Large number of imaginary frequencies with ROKS and delta SCF
Questions
1 153 February 19, 2026