The Reference Pattern Database

Match! identifies phases in a sample by comparing its powder diffraction pattern to reference patterns of known phases. Hence, it needs a so-called "reference database" in which these reference patterns are provided. The reference databases are managed in the so-called "Reference Database Library" dialog.

There are several options for obtaining a reference database:

We have run several tests in order to evaluate the quality of the various reference databases mentioned above:

Compared to using the classical ICDD PDF database, our tests reveal a somewhat diverse performace when using the free-of-charge COD reference patterns: When mineral samples were investigated, the results were generally very good, thanks to the excellent coverage of the AMCSD (which is included in the COD). Even for many samples other than minerals, the correct phases were identified in most cases, however, we found some (few) samples where main phases were not recognized because the corresponding reference patterns were not present in the COD reference database. In all cases, it was no problem to identify all phases when using the ICDD PDF-2 Release 2007 database.

According to our experience, it is optimal to combine the COD database (which basically contains more recent entries) with a user database created from ICSD/Retrieve (which typically contains "older" entries). Using such a combined reference database is the best solution if you do not have a recent ICDD PDF database available!

Hence, if you are investigating mineral or similar samples, you should be fine using the free-of-charge COD reference database. For most other users, it is currently advisable to either add ICSD/Retrieve reference patterns to the COD database, or use the conventional ICDD PDF-2 or PDF-4 database.

Please note: