Definition of Quality Marks regarding Powder Diffraction Cards

Quality Mark
The quality mark option allows the user to select only patterns for which the appropriate quality mark is prescribed. The quality mark selection can be "*" (star quality pattern); an "I" (indexed pattern); a "0" (low precision pattern); a "C" (calculated pattern); an "R" (Rietveld pattern); or a "blank" (undefined quality pattern). The user may also select "All" (which is also the default value); that causes the program to select all patterns independently of the quality mark.

Any one of the following Quality Marks can be chosen:

"*" A "Star" quality pattern represents high quality diffractometer or Guinier data; the chemical composition is well characterized; intensities have been measured objectively; and no serious systematic errors exist. The average delta 2theta is less than 0.03 deg.

"I" An "Indexed" quality mark indicates that the pattern has been indexed (thus is almost certainly single phase). There is a reasonable range and even spread in intensities; there are no serious systematic errors and the average delta 2theta is less than 0.06 deg.

"0" A "Zero" quality mark means that the diffraction data have been taken on poorly characterized material or that the data are known (or suspected) to be of low precision.

"B" A "Blank" quality mark is assigned to patterns which do not meet the "*", "I", or "0" criteria

"R" A "Rietveld" quality mark is used for patterns where it is clear that the d-values are directly the result of Rietveld refinement of the data. However, Rietveld refinements are accepted only in unusual cases.

"C" A "Calculated" quality mark is assigned to those patterns which have been calculated from single crystal data. C patterns generally have very precise d-values, but the intensities may not reflect what is obtained in an experimental pattern.