Need for Reference State Definitions

[PTA0001]

1. There exists a need for various options of reference state definitions:
   • Setting entropy reference and enthalpy reference(while this can be any arbitral constant for non-reactive systems, it becomes important for reactive systems and leads to point number 2)
   • Setting Gibbs energy reference and enthalpy reference(mostly for reactive systems using the heat of formation but also applicable to non-reactive systems )
2. Clarity of entropy reference state as defined by the third law of thermodynamic(absolute entropy reference) and entropy of formation.
3. with the aforementioned, the reference state variables cannot be defined by specific property methods as this will lead to dependencies or inconsistencies. Alternatively, the current specific methods e.g RPP4 need to take into account the various options for reference state specifications.