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 1643 November 22, 2024
NAC rem variable error
Questions
1 82 August 5, 2026
ALMO_EDA job failure
Questions
3 542 August 10, 2026
BSSE error input file
Questions
5 639 August 10, 2026
Electron Coupling Calculation with CDFT and CDFT-CI approach
Questions
0 73 August 5, 2026
Webinar 88: What's new in Q-Chem 7
Announcements
0 101 July 28, 2026
CDFT-CI convergence issue
Questions
1 111 July 26, 2026
BOMD of two cationic fragments (coulomb explosion)
Questions
1 143 July 24, 2026
Help with incremental FCI (iFCI) example
Questions
1 879 March 12, 2023
Some doubt regarding CAP onset
Questions
3 155 July 6, 2026
Calculation of transition density matrices between CVS-ADC(2)-x excited states
Questions
0 152 June 30, 2026
Unexpected Energy Ordering in TDDFT Nonequilibrium PCM
Questions
1 177 June 24, 2026
Amber force field generation
Questions
3 237 June 23, 2026
What sort of SCF calculations are supported with external fields?
Questions
5 254 June 16, 2026
CDFT-CI Coupling convergence issue
Questions
5 268 June 15, 2026
ALMO-EDA/COVP SCF Convergence Failure for Open-Shell Anion Radical System
Questions
6 336 June 13, 2026
Lowering amplitude threshold when doing eom CCSD job
Questions
0 185 June 11, 2026
Error in RI-EA-CC2 calculation
Questions
4 437 June 7, 2026
FCIDUMP support
Questions
1 213 June 5, 2026
Upgrade to DFT-D4 in QChem 6.4
Questions
1 243 June 4, 2026
Electronic structures of TDDFT-1D states
Questions
0 227 June 2, 2026
Challenges in CDFT Geometry Optimization Using aug-cc-pVDZ
Questions
1 248 May 29, 2026
Simulating Vibronic and Resonance Raman Spectroscopy Using the VIBRONIC module of Q-Chem
How To
18 4634 May 25, 2026
QM/EFP Setup in Q-Chem with Ghost Atoms Only (Excess Electron in Cavity)
Questions
1 1778 May 22, 2026
Restarting finite difference frequency jobs
Questions
4 1777 May 18, 2026
“ADC(3) singlet and triplet excited states with PCM – input and disk quota issues”
Questions
4 688 May 18, 2026
aug-cc-pV5Z with external charges
Questions
3 349 May 13, 2026
CDFT block set up
How To
1 318 May 7, 2026
New basis set - excited states of Argon
Questions
3 397 May 5, 2026
PES scan not respecting mem_total
Questions
6 347 May 4, 2026