This namespace contains constants used by the class
OEMultistatepKaModel to define what is
the assessed atomic pKa range of the atom according to the multistate model.
The atom has Acidic pka range (<6.4).
The atom has Basic pka range (>8.4).
The atom has Neutral pka range (between 6.4 and 8.4).
The atom’s pKa range is unidentified by the multistate pka model.
This constant represents an undefined or illegal context state.