Quality Criteria

All data included in the thermodynamic reference database are assigned identifiers for "source", "quality", "category", and "class" as is described below. This shall guide the user when applying THEREDA data to specific application cases. Namely, such information helps to compute complex systems with sparse data and disputed sets of chemical species. It also permits an estimation of consequences of uncertain system understanding or numerical data.

Data Source

-1	Value is internally calculated from entered data.
0	Per definition / convention fixed value.
1	Datum adopted from a critical data collection with external review (e.g. CODATA, NEA-TDB, PSI-TDB-Report).
2	Datum adopted from an internationally acknowledged review article (e.g. in IUPAC Solubility Data Series, Am. J. Sci. or Coord. Chem. Rev.).
3	Datum is based on an article in a peer-reviewed journal.
4	Datum adopted from an institutional report, Book, Ph.D. thesis, THEREDA-Journal (or similar publications, all without international or external review)
5	Datum is from an internal source not available to the public, but available to editors of THEREDA.
6	Data source yet to be entered.

Quality Level

-1	Value is internally calculated from entered data.
0	Per definition / convention fixed value.
1	Recommended datum (A model value that has been reviewed and recommended by the THEREDA team and has been shown in tests to be capable of reproducing experimental results.)
2	Supplemental/provisional datum (A model value that can be used for modeling with certain limitations, but for which no better value is available, or whose omission would lead to significantly worse results.)
3	Questionable datum (uncertain model for speciation, uncertain auxiliary data), but nevertheless suitable and necessary for the description of chemical systems with questionable experimental data or where no experimental data are available at all.
6	Data quality yet to be entered.

Data Category

F	Formation data
R	Reaction data

 

Data Classes for formation data (F)

-1	Value is internally calculated from entered formation data (category F).
0	Formation data, by definition or convention.
1	Value based upon experimental formation data.
2	Chemical analogue value, based upon experimental formation data.
3	Estimated value, based upon founded correlations and models for formation data.
4	Origin of value not reported, but probably of formation type; data class cannot be determined.
5	Experimental formation data, not consistent with other data in THEREDA.
6	Formation data, dataclass has not yet been assigned.

 

Data Classes for reaction data (R)

-1	Internally calculated from reaction data (category R).
0	Reaction data, by definition or convention.
1	Value based upon experimental reaction data.
2	Chemical analogue value, based upon experimental reaction data.
3	Estimated value, based upon founded correlations and models for reaction data.
4	Origin of value not reported, but probably of reaction type; data class cannot be determined.
5	Experimental reaction data, not consistent with other data in THEREDA.
6	Experimental reaction data, dataclass has not yet been assigned.

Data Classes for interaction parameters

-1	Value is internally calculated from a p, T-function (CalcMode CTPFUNC).
0	By definition / convention fixed value.
1	Value based upon experimental equilibrium data.
2	Chemical analogue value, based upon experimental equilibrium data.
3	Estimated value, based upon founded correlations and models.
4	Tentative value for unknown interaction parameters, which cannot be estimated.
5	Not consistent with other data in THEREDA.
6	IPClass not yet entered (to be done).

 

Addional elements for quality assurance

• All data included in THEREDA are assigned, if possible, an uncertainty.

• All data included in THEREDA must be internally consistent.

• Dependencies between data and parameter, which are crucial for internal consistency, must be annotated and visible for the user.

• As far as possible, selection of data shall be accounted for in attached documents, available for the user.

• Parameter files made available from contributors to the THEREDA-project have to undergo a series of pre-defined test calculations.