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	3980	August 12, 2019
Welcome to the PSI4 Forum!	1	23364	July 16, 2015
One electron Density Matrix diagonals don't sum to 1	0	2	January 18, 2025
Lmax exceed, cc-pv8z	2	46	January 13, 2025
DFT with a custom starting `Da` & `Db`	1	26	January 9, 2025
Calculating the first order electrostatic energy in the monomer basis using Psi4Numpy SAPT	5	843	December 28, 2024
Could Someone Give me Advice on Developing a New PsiCode Plugin?	0	17	December 26, 2024
PSA: Psi4 Installers Down	0	29	December 24, 2024
Unable to download installer for Psi4conda: Permission? build	3	36	December 24, 2024
Using Field Programmable Gate Array Acceleration?	2	34	December 16, 2024
Simple CCSD calculation fails for a large molecule build	3	53	December 15, 2024
Optimizing a P4 molecule causes error "local variable 'errors'..." Geometry Optimization	1	34	December 12, 2024
Temperature options	2	27	December 9, 2024
Unrecognized point group bits with a custom functional (CASE21) Geometry Optimization	0	18	December 7, 2024
Confusion about PsiAPI and polarizability calculations	0	19	December 5, 2024
Number of Basis Functions is Mismatched/Inconsistent!	2	28	November 19, 2024
Why does nuclear_repulsion_energy depend on the external electric field?	1	27	November 19, 2024
Does Psi4 Support Complex SCF?	1	33	November 18, 2024
My custom code isn't passing tests, help!	5	65	November 18, 2024
Dipole moment finite-field computation Psi4Education	2	31	November 15, 2024
Problem with dftd4 installation build	3	72	November 9, 2024
How to compute the SCF unrelaxed energy?	3	45	November 9, 2024
Spherical averaging of occupied orbitals on atoms	5	926	January 20, 2021
MP2 polarizability using finite field	5	1748	January 3, 2025
What's wrong with my attempt to test Brillouin's Theorem?	3	41	October 31, 2024
What's wrong with my attempt to reproduce the dipole moment?	2	39	October 31, 2024
Why am I getting strange results for transition metals in Psi4 1.5?	17	59	October 29, 2024
Where is psi4_dev located?	2	24	October 28, 2024
Multi-threading two-electron integrals	0	28	October 27, 2024
Installtion of PSI4 Psi4conda-1.9.1-py38-Linux-x86_64.sh Geometry Optimization	0	30	October 21, 2024

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…