Questions tagged [psi4]

For questions about using the Psi4 Quantum Chemistry Package.

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7
votes
1answer
83 views

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 ...
5
votes
1answer
84 views

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 ...
8
votes
1answer
77 views

Error running psi4 on charged molecules

I am running a simple energy calculation on a conformer of 3-Sulfopropyl methacrylate, which is given my C=C(C)C(=O)OCCCS(=O)(=O)[O-]. This is my workflow: ...
8
votes
2answers
252 views

How do I figure out how many monomer configurations I need for my simulation?

I am running a quantum mechanical simulation on Psi4 for a certain number of monomers to generate data for a database. Some of these monomers are short, while some are long. At the moment, I am ...
7
votes
2answers
158 views

What do the indices mean in an FCIDUMP file?

I generated an FCIDUMP file, which is copied below ...
17
votes
1answer
328 views

Alternatives to VEDA 4 vibrational energy distribution analysis software?

Said software is useful when you need to assign the peaks in vibrational spectra to different vibrational modes found in a hessian calculation for a given molecule, as described in Jamróz, Michał H. “...
18
votes
1answer
161 views

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 ...