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Questions tagged [psi4]

For questions about using the Psi4 Quantum Chemistry Package.

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18 votes
1 answer

Exchange-Correlation Two-Electron Integrals

Do any freely available or proprietary electronic structure packages explicitly compute two-electron exchange correlation integrals? I have found a few derivations to calculate excited state ...
Tyberius's user avatar
  • 15.6k
9 votes
2 answers

What do the indices mean in an FCIDUMP file?

I generated an FCIDUMP file, which is copied below ...
fagd's user avatar
  • 231
7 votes
1 answer

Computing analytic derivatives of molecular Hamiltonians obtained from solving Hartree-Fock equations

I'm currently working on a quantum chemistry project, I am dealing with a second-quantized electronic Hamiltonian (corresponding to some molecule), written in terms of fermionic creation and ...
Jack Ceroni's user avatar
5 votes
1 answer

Calculating first and second derivatives of a molecular Hamiltonian?

I'm interested in computing first and second derivatives of molecular Hamiltonians with respect to nuclear coordinates. I've been using Psi4 and PySCF to perform Hartree-Fock calculations, and I was ...
Jack Ceroni's user avatar
1 vote
1 answer

How do I install the beta5 version of PSI4 on my WebMO Basic server?

Installing the basic version of PSI4 on my personal LG Gram 360 (with a Windows OS), used as a my-own WebMO Basic server, was done according to the WebMO tutorial. I then tried to compute the energy ...
Kanghun Kim's user avatar