Charges (AKA populations)

[mattwelborn]

Add atomic charges/populations to the schema. The field needs to carry information about both the charge method and the electronic structure method. One possibility is to use our current convention and name fields like scf_lowdin_charges, scf_mulliken_charges, etc.

Another would be to keep the method in the name, but then have a list of charge methods, e.g.

{
  "scf_charges": [
    {"charges": [1,2,3,4],
      "charge_method": "lowdin"
    },
    {"charges": [5,6,7,8],
      "charge_method": "mulliken"
    }
  ]
}

Or finally, it could just be a great big list:

{
  "charges": [
    {"charges": [1,2,3,4],
      "charge_method": "lowdin",
      "method": "scf"
    },
    {"charges": [5,6,7,8],
      "charge_method": "mulliken",
      "method": "mp2 relaxed"
    }
  ]
}

[dgasmith]

Worth thinking about other one electron properties like bond orders, ESPs, electronegativity, frequencies, etc. Best to work through a wholistic solution in this space so that everything can be consistent.

[mattwelborn]

Speaking of bond orders: MolSSI/QCFractal#414