Add gradient, Hessian, and orbital coeffs scratch file parsers to pymatgen.io.qchem.outputs

[Andrew-S-Rosen]

Summary

This PR adds function to pymatgen.io.qchem.outputs to parse (scratch) gradient, Hessian, and previous orbital coefficient files made by Q-Chem.

Note: 99% of the credit for this goes to @samblau. I am simply moving it into pymatgen where it belongs.

Todos

I need to add tests. There are also some things that are definitely better done with numpy vectorization, but it's not a huge issue.

Checklist

• Google format doc strings added. Check with ruff.
• Type annotations included. Check with mypy.
• Tests added for new features/fixes.
• [] If applicable, new classes/functions/modules have duecredit @due.dcite decorators to reference relevant papers by DOI (example)

Tip: Install pre-commit hooks to auto-check types and linting before every commit:

pip install -U pre-commit
pre-commit install

[Andrew-S-Rosen]

@janosh: This should be ready for review. As I mentioned above, this code was largely written by @samblau --- I added some simple tests and cleaned up the linting errors. Longer term, it would probably make sense to create a new QCScratch(MSONable) class that parses scratch files in a directory. However, I have not implemented that here (unless you feel it necessary).

[janosh]

Thanks @Andrew-S-Rosen, looks great! Just a minor suggestion re test file compression.

it would probably make sense to create a new QCScratch(MSONable) class that parses scratch files in a directory. However, I have not implemented that here (unless you feel it necessary).

Tbh I don't feel qualified to make that call

[Andrew-S-Rosen]

@janosh: Thanks! I gzip'd the files. Should be good to go from my end at least :)

[Andrew-S-Rosen]

@janosh: All good now!

[janosh]

Thanks @Andrew-S-Rosen! 👍