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	1311	November 22, 2024
Memory and RICIS(D) calculations Questions	2	10	March 11, 2026
MRSF: differences between Q-Chem and OpenQP Questions	0	38	March 8, 2026
SOC for unrestricted TDDFT Questions	3	213	March 6, 2026
Gradient and Hessian using CCSD and EOM-CCSD Questions	3	55	March 5, 2026
Resolution of identity for CDFT? Questions	6	90	March 3, 2026
ROHF energy discrepancy between Q-Chem and CFOUR Questions	4	109	February 28, 2026
Optimal settings for large DFT calculations Questions	3	473	February 28, 2026
Using FRAGMO with ptSS-PCM and CDFT for Vertical Electron Transfer Calculation Questions	3	76	February 26, 2026
Geometry Optimization with SS_PCM Questions	1	80	February 25, 2026
Thresh/s2thresh 14? Questions	8	101	February 24, 2026
Normal Modes Question Questions	3	230	February 23, 2026
Symmetry in CCSD(T) frequency calculation Questions	4	108	February 23, 2026
Symmetry of EOM-EA-CCSD. Significance? Questions	1	113	February 21, 2026
Units of vibrational eigenvectors Questions	2	128	February 20, 2026
EOM-EA-CCSD on a Excited state Questions	1	92	February 20, 2026
ROKS emission energy with nonequilibrium solvent Questions	0	79	February 20, 2026
Dyson orbital using EOMCCSDT-IP Questions	1	104	February 20, 2026
Frequency calculation speedup Questions	1	203	February 19, 2026
What is the correct input for the GEOM_OPT_MODE Questions	2	120	February 19, 2026
Large number of imaginary frequencies with ROKS and delta SCF Questions	1	92	February 19, 2026
Ehrenfest Molecular Dynamics Questions	2	92	February 19, 2026
S1 Geom optimization based on TDDFT and delta SCF approach Questions	11	187	February 18, 2026
Q-Chem license on new MacOS How To	0	111	February 17, 2026
Stuck CCSD frequency calculation Questions	2	124	February 16, 2026
Issue with designing functionals Questions	4	100	February 15, 2026
COSMO input file Questions	2	110	February 13, 2026
VQCCD single point calculation issue Questions	0	100	February 13, 2026
RIXS with TDDFT Questions	0	95	February 12, 2026
Wrong multiplicity for large multiplicity element when using projection based embedding Questions	3	106	February 12, 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…