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Questions tagged [psi4]

For questions about using the Psi4 Quantum Chemistry Package.

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4 votes
1 answer

What is the best way to save a psi4 molecule object in Python?

what is the best way to save and load a psi4 molecule? I tried pickle/dill but they both failed. I see a feature to save as xyz, but I'm not seeing a function to load as xyz and I'm not sure if save ...
4 votes
0 answers

OOM Error Calculating ESP Charges with Psi4

I'm trying to create a script to generate partial charges for a given .dat file. As an example of my process, I'm currently using gromacs to run minimization on a box of propane. It outputs a min.gro ...
3 votes
1 answer

PSI4 SAPT calculation: failure to write

I am attempting to run SAPT0 calculations on dimer complexes with around 100 atoms each. However, PSI4 SAPT0 calculations freeze and get terminated with the following error messages - I assigned 48GB ...
3 votes
1 answer

Psi4 functionnals: LDA0

When comparing the energy of the LDA0 and SVWN (Slater exchange and VWN(1980) correlation), I get different results. So what is the LDA0 functional in Psi4? I can't really find literature about it.
4 votes
1 answer

Psi4 Takes too Long to Save Computation Results to Python Notebook

I was using psi4 to run vibrational frequency analysis with small molecules (in a jupyter notebook) and it works just fine with molecules like methanol and water but once I move up to ethanol or ...
3 votes
1 answer

Decay rate of DSD-PBEPBE-D3BJ

I gave up on the wB97X-2(TQZ) functional, which would have an exact decay rate of -1/r, re: my previous question and decided to use DSD-PBEPBE-D3BJ, which is available on vanilla Psi4. I then looked ...
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 ...
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 ...
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 ...
9 votes
1 answer

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: ...
17 votes
1 answer

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. “...
8 votes
2 answers

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 ...
9 votes
2 answers

What do the indices mean in an FCIDUMP file?

I generated an FCIDUMP file, which is copied below ...
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 ...