Psi4 – Open-Source Quantum Chemistry

Topic	Replies	Views	Activity
Making Topics that Get Answered Most questions that are answered on the Psi4 Forums are answered by a small group of developers and powerusers. Their time and energy is divided between their own research, further Psi development, and helping users. Acc…	2	4007	August 12, 2019
Welcome to the PSI4 Forum!	1	23385	July 16, 2015
Spin-orbital correction	0	4	March 10, 2025
Bug report psio	0	9	March 6, 2025
Single point job stops over 65 atoms; no error message	0	22	March 4, 2025
DLPNO-CCSD(T) method feature-request	2	61	March 4, 2025
Out of memory using PCM model: Geom. optimization of lithiated ethylene carbonate Geometry Optimization	3	444	March 1, 2025
Def2-universal-jkfit and def2-tzvpp-ri bases? SAPT	0	23	March 1, 2025
Statically-linking Psi4 build	3	45	February 18, 2025
Investigating a chalcogen interaction with i-sapt SAPT	0	23	February 15, 2025
Challenges in Locating the Transition State for Meisenheimer Complex Formation in the SNAr Reaction of 4-Chloropyridine with Azide Anion Geometry Optimization	0	15	February 14, 2025
Error when using psi4/resp: Fatal Error: RHF: RHF reference is only for singlets SAPT	1	26	February 13, 2025
Colab GPU Accelerator Config build	0	28	February 9, 2025
UnboundLocalError for geometry optimization of Li4 with python module psi4 Geometry Optimization	2	26	February 3, 2025
Fractional occupation with PsiAPI	1	18	February 3, 2025
IOH augmented base	2	21	January 27, 2025
One electron Density Matrix diagonals don't sum to 1	9	82	January 22, 2025
Does Freeze Core also impact full La-group shells? Geometry Optimization	0	16	January 21, 2025
Excited states dipole moment	2	23	January 21, 2025
Gorling-Levy perturbation theory feature-request	0	16	January 18, 2025
Lmax exceed, cc-pv8z	2	58	January 13, 2025
DFT with a custom starting `Da` & `Db`	1	38	January 9, 2025
Calculating the first order electrostatic energy in the monomer basis using Psi4Numpy SAPT	5	857	December 28, 2024
Could Someone Give me Advice on Developing a New PsiCode Plugin?	0	26	December 26, 2024
PSA: Psi4 Installers Down	0	46	December 24, 2024
Unable to download installer for Psi4conda: Permission? build	3	70	December 24, 2024
Using Field Programmable Gate Array Acceleration?	2	37	December 16, 2024
Simple CCSD calculation fails for a large molecule build	3	67	December 15, 2024
Optimizing a P4 molecule causes error "local variable 'errors'..." Geometry Optimization	1	47	December 12, 2024
Temperature options	3	32	February 7, 2025

Making Topics that Get Answered

Most questions that are answered on the Psi4 Forums are answered by a small group of developers and powerusers. Their time and energy is divided between their own research, further Psi development, and helping users. Acc…