Q-Chem Talk

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	1338	November 22, 2024
SCF convergence problem in CDFT-CI calculation Questions	1	40	March 20, 2026
NAC calculation Questions	1	50	March 18, 2026
Strange outcome in RAS-SF calculation Questions	0	39	March 17, 2026
Speeding up ADC(2) calculations Questions	2	63	March 17, 2026
Is it possible to print gradients of several excited states? Questions	3	87	March 14, 2026
Memory and RICIS(D) calculations Questions	4	71	March 11, 2026
MRSF: differences between Q-Chem and OpenQP Questions	0	84	March 8, 2026
SOC for unrestricted TDDFT Questions	3	259	March 6, 2026
Gradient and Hessian using CCSD and EOM-CCSD Questions	3	85	March 5, 2026
Resolution of identity for CDFT? Questions	6	120	March 3, 2026
ROHF energy discrepancy between Q-Chem and CFOUR Questions	4	149	February 28, 2026
Optimal settings for large DFT calculations Questions	3	494	February 28, 2026
Using FRAGMO with ptSS-PCM and CDFT for Vertical Electron Transfer Calculation Questions	3	99	February 26, 2026
Geometry Optimization with SS_PCM Questions	1	115	February 25, 2026
Thresh/s2thresh 14? Questions	8	126	February 24, 2026
Normal Modes Question Questions	3	269	February 23, 2026
Symmetry in CCSD(T) frequency calculation Questions	4	137	February 23, 2026
Symmetry of EOM-EA-CCSD. Significance? Questions	1	146	February 21, 2026
Units of vibrational eigenvectors Questions	2	172	February 20, 2026
EOM-EA-CCSD on a Excited state Questions	1	116	February 20, 2026
ROKS emission energy with nonequilibrium solvent Questions	0	109	February 20, 2026
Dyson orbital using EOMCCSDT-IP Questions	1	139	February 20, 2026
Frequency calculation speedup Questions	1	253	February 19, 2026
What is the correct input for the GEOM_OPT_MODE Questions	2	158	February 19, 2026
Large number of imaginary frequencies with ROKS and delta SCF Questions	1	119	February 19, 2026
Ehrenfest Molecular Dynamics Questions	2	131	February 19, 2026
S1 Geom optimization based on TDDFT and delta SCF approach Questions	11	219	February 18, 2026
Q-Chem license on new MacOS How To	0	140	February 17, 2026
Stuck CCSD frequency calculation Questions	2	154	February 16, 2026

Report SCF (HF/DFT) Convergence Issues

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…