Charge, mass, formula¶

These are properties of the Chemical System:

property ChemicalSystem.charge: float

The total charge of the system in atomic units (i.e. in units of elementary charge).

ChemicalSystem.total_mass() → float

Total mass in atomic mass units (dalton).

To set or get the mass of individual atoms, see Atom Attributes.

ChemicalSystem.formula() → str

Chemical formula in Hill notation (e.g. H2O, CH4):

• If Carbon is present, the order is: C, H, alphabetical.

• If Carbon is not present all the elements (including Hydrogen) are listed alphabetically.

• Single-letter elements come before 2-letters elements (e.g. ‘K’ comes before ‘Kr’, ‘B’ before ‘Be’)