(Conversation from PR #295)

Gaussian writes several thermochemistry magnitudes when a freq calculation is requested, namely (some of them already being parsed):

• Temperature
• Pressure
• Zero-point correction
• Thermal correction to Energy
• Thermal correction to Enthalpy
• Thermal correction to Gibbs Free Energy
• Sum of electronic and zero-point Energies
• Sum of electronic and thermal Energies
• Sum of electronic and thermal Enthalpies
• Sum of electronic and thermal Free Energies

However, do we really want more ccData attributes for them? @berquist mentioned that:

We should avoid redundant/non-unique attributes if possible.

So we would need to assess if those magnitudes are either:

• Available in the output from other suites. In this case, fields could be added and parsing code should be written.
• Not available, but computable. A method should be added.
• Not available, not computable directly. Mention that in the docs. Users that want to retrieve that data should subclass and add the parsing code themselves (what I am doing with esigen right now).

This issue is to resolve that discussion and proceed as decided.