PDF_Editorial_2

							Calc. Patterns Quality Marks in
         Release 2005
         Suri Kabekkodu
• A calculated patterns quality mark task
  group was formed during the ICDD spring
  meeting 2003 in order to develop a method
  to assign quality marks to calculated
  patterns.
• S. Kabekkodu (Chair), C. Hubbard,               J.
  Kaduk, E. Antipov, M. Bennett, P. Wallace, F.
  Rotella
      Scope and Considerations
• The focus of the quality mark is to determine the
  confidence level of the structural model used and
  its impact on the calculated pattern (especially for
  the purpose of phase identification).
• The method should involve rigorous
  crystallographic and additional editorial checks by
  the ICDD and warning comments from our
  collaborating structural databases
  (ICSD/CSD/NIST/LPF).
         Program Development
• Several crystallographic and other data checking
  programs were developed by the ICDD to achieve
  this goal.
• To name a few
   • Temperature factors analysis
      • Non positive definite matrix check
      • Range check
   • Checking the space group choice of origin
   • Composition check (reported Vs refined)
   • Several “keyword” based queries to extract external
     database comments/warnings
                       Distribution of QM in Calc Patterns
               4
        6 10


               4
        5 10


               4
        4 10
Count




               4
        3 10


               4
        2 10


               4
        1 10



           0
                   O         H          I         S          B

                                       QM
                            LPF

                       Qulaity Marks Distribution in LPF
               4
        5 10



               4
        4 10



               4
        3 10
Count




               4
        2 10



               4
        1 10




           0
                   O        S         B           I        P

                                      QM
                               ICSD

                         Quality Marks Distribution in ICSD Data
                 4
         3 10


                 4
        2.5 10


                 4
         2 10
Count




                 4
        1.5 10


                 4
         1 10



         5000



             0
                     O           H          I         S            B

                                           QM
                         NIST

                   Quality Marks Distribution in NIST Data
               4
        1 10




        8000




        6000
Count




        4000




        2000




           0
                   O           S            B                I

                                     QM
          Population of Editor’s comments after
        assigning quality mark to all the calculated
                    patterns(394,175)

SOURCE      NUMBER     MINOR   SIGNIFICANT MAJOR   TOTAL
DATA        OF         WARNING WARNING     WARNING
            ENTRIES

LPF            78769      71121       8766       3   79890
ICSD           68404      45874      38037     372   84283
NIST            9802      15784       1559      10   17353
CSD           237200     106772      51455     423 161350
Total         394175     239551      99817     808 342876