Data Mining the Powder Diffraction File, Present and Future Capabilities

The objective of data mining is to sort through large amounts of data in order to find a particular result that the user is searching for. As the size of the database being searched grows the probability of finding the result increases. However the path traveled to find the result may get more difficult. There are many challenges in deciding which turn to take, and information to keep, in the search for a particular result. The Powder Diffraction File (PDF™) has grown dramatically in the past five years due to a series of strategic collaborations with global database organizations. There are now 157,048 entries in the PDF-2 and PDF-4/Full File Release 2003 databases and 218,194 entries in PDF-4/Organics Release 2004. Each entry contains chemical and empirical formula, structural classifications, bibliographic, crystallographic and physical data as well a diffraction pattern that can be digitally displayed or presented as an indexed listing of d-spacing and intensity pairs. Therefore each entry can contains hundreds to thousands of pieces of information. The total compilation of the PDF has more than 650,000 literature reference citations from over 150,000 authors of x-ray analyses compiled since the earliest published studies. The task facing many users of the Powder Diffraction File™ now becomes the efficient use and searching of this large amount of data to find exactly the information that they are seeking. In this paper we will describe the many paths that can be taken to explore the perovskite family of materials. In the last several years new database tools have been developed to aid researchers in exploring the database. The database itself has been reorganized in a relational database format which consists of numerous tables that can be easily cross referenced and queried. A new display program, DDView has been developed that allows all data fields to be ordered by the user and sorted by their personal preference. Finally, the utility program SIeve, automates and evaluates data relative to the classical searches and indexes such as Fink, Hanawalt and Long 8, can automatically import various files containing d, I pairs and is seamlessly interfaced to DDView. The use of multiple search paths results in the proper identification and classification of many materials that weren’t previously identified as perovskites. Keyword Search: Data Mining, Powder Diffraction File, Perovskites Results Perovskites are a rich class of important materials well known by mineralogists, ceramists and chemists for their unusual chemical and electronic properties. It is well recognized [1, 2] that perovskites have distinct structural characteristic that provide insights into their various physical properties. Because of this fact scientists have frequently tried to collect structural information on this important class of materials in order to examine physical characteristics and properties. Historically several editorial teams, typically consisting of field experts, have tried to define and classify these materials at the international database organizations. Yet if a novice explores these databases they would find various answers to simple questions such as how many perovskites are known? What are their chemical compositions? How are they defined? The Powder Diffraction File has grown dramatically due to collaborations with other database organizations. A consequence of these collaborations is that the combined output of several different editorial teams from several organizations are now available in a single product. This combined knowledge while powerful can be confusing because the answer you get depends on how you ask the question (definition and convention) and how many questions you ask (i.e. the paths that you take). Using a relational database format allows the user to use any field parameter as a query. Table I shows the general types of information that are available in the Powder Diffraction File relational database. id372074453 pdfMachine by Broadgun Software a great PDF writer! a great PDF creator! http://www.pdfmachine.com http://www.broadgun.com