Issue 285: Add ionization energy data from NIST

[chasepd]

Description

Adds ionization energy data from NIST to the particle data json files, as well as a property in the Particle class to retrieve this information. Returns a descriptive MissingParticleDataError if ionization energy data is not available for the particle.

Motivation and context

Addresses the requested feature at: #285.

A commonly needed in plasma physics is the energy it takes to ionize a single atom or ion. The Particle class should have an attribute called ionization_energy that returns this value.

Related issues

#285

[github-actions]

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[chasepd]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.23%. Comparing base (79b1c19) to head (793270a).
Report is 6 commits behind head on main.

❗ Current head 793270a differs from pull request most recent head c0e42bb. Consider uploading reports for the commit c0e42bb to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2657      +/-   ##
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+ Coverage   95.21%   95.23%   +0.01%     
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  Files         103      104       +1     
  Lines        9412     9435      +23     
  Branches     2155     2159       +4     
==========================================
+ Hits         8962     8985      +23     
  Misses        273      273              
  Partials      177      177              

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[chasepd]

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[pheuer]

Very nice start! Here are a few minor corrections.

There is one larger bug: right now, this code still returns the ground state ionization energy even if the particle is an ion, e.g.

Particle('C +2').ionization_energy == Particle('C +0').ionization_energy
>True

while, according to the NIST tables, the ionization states above should be 47 eV and 11 eV respectively. I can see two ways of fixing this:

1. Make this property only available for particles corresponding to neutral atoms

2. Much more ambitious: implement this property for all of the ion charge states!

If you chose the second path, I would recommend the following:

1. Download the data for every element in the NIST database as a CSV
2. Write a python script that takes that data and puts it into a single json file that you can add to the particles/data folder. You could add different isotopes there too.
3. In the attribute, determine the isotope, charge, and nucleus of the particle and return the appropriate value from your json file.

No pressure to go the second path if you don't want to, just adding this for neutral atoms would be a nice start! But thought I'd offer it as a suggestion since you seem to have handled this pretty easily :)

[pheuer]

This looks great! Thanks for adding the downloader script!

One remaining bug I found: you have separate data for deuterium (H-2) and hydrogen (H-1), but it looks like with the current logic both of these get interpreted as 'Hydrogen' so you never actually get the value for Deuterium. It's only slightly different, but sine you have the data in there it would be good to have it return the right one!

You could maybe add one more test for for this exception (since in all the other cases, you do have a test that correctly shows that the different isotopes have equal ionization energies).

To be clear on the physics, technically all of the isotopes have different ionization energies, but the difference is just vanishingly small above He so it's not measurable.

Particle('H').ionization_energy == Particle('D').ionization_energy == Particle('H-2').ionization_energy
>True

Should return False

[chasepd]

pre-commit.ci autofix

[pheuer]

Looks great @chasepd , thanks so much for putting this together!