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…

3 732 November 22, 2024
Large system Hessian crash
Questions
1 30 September 15, 2025
A question about exploring a transition state
Questions
4 122 September 15, 2025
Are there specific command to print the gradient matrix?
Questions
2 47 September 12, 2025
Visualizing Frequencies from Partial Hessians calculation
Questions
5 50 September 11, 2025
EOMCCSDT calculations
How To
0 31 September 10, 2025
Pump-probe NEXAFS (TR-XAS)
Questions
8 293 September 10, 2025
How to Verify if Optimized SF-TDDFT MECP (Penalty Function) is a True MECP or Artificial?
Questions
3 47 September 10, 2025
Which V-coupling value of energy transfer is correct?
Questions
6 69 September 4, 2025
Transition (dipole) moment
Questions
11 3659 August 29, 2025
Difference between TD-DFT and Internal Stability?
Questions
1 87 August 28, 2025
Issues with Slippage in Head-to-Head stacked composites during CDFT optimization
Questions
1 88 August 28, 2025
OPE Spectra with solvent
Questions
1 79 August 27, 2025
Q-Chem failing to recognize correct symmetry
Questions
6 136 August 22, 2025
Enforcing D2h during 2D PES_SCAN for cyclobutadiene
Questions
1 86 August 22, 2025
CASSCF frequency crashes in FILE_NUCLEAR_HESSIAN
Questions
12 178 August 21, 2025
Using DC vs HF-DFT
Questions
2 84 August 20, 2025
STATE_ANALYSIS incompatibilities with TD-DFT
Questions
6 730 August 18, 2025
Phase of NTO from hole.cube and elec.cube
Questions
8 183 August 18, 2025
NTO Analysis
How To
9 178 August 17, 2025
Crashed CASSCF TS optimization
Questions
1 90 August 14, 2025
Quadrupole Tensor Calculation in TDDFT
Questions
2 98 August 10, 2025
B3LYP+XDM and RI problem
Questions
3 243 August 10, 2025
Problem with CCSD(T) optimization followed by subsequent NBO and other calculations
Questions
4 189 August 4, 2025
TDDFT-1D Convergence Issue
How To
8 202 July 30, 2025
Is it possible to plot transition densities between TDDFT excited states
Questions
8 189 July 28, 2025
Spin adapted-SF-DFT
Questions
2 174 July 22, 2025
How to calculate T-T absorption energy of excited T1 state
Questions
3 174 July 21, 2025
Point charge handling in QChem
Questions
2 135 July 13, 2025
FSM string distribution
Questions
1 128 July 10, 2025