Also See - Corrective Downloads
1. Why doesn't the ICDD produce more software particularly search/match, Rietveld and other data analysis software?
Since the earliest data of automated diffractometers in the 1970's, the ICDD has worked in close partnership with software vendors and equipment manufacturers to bring automated data collection, identification, and pattern analysis to the global community. This teaming of resources allows the ICDD to keep prices low and allows the software and equipment manufacturers to focus their resources on equipment and data analysis rather than standard collection and publication. In turn, the ICDD focuses its resources on x-ray analysis education, standard collection, editing, and publication of the database. The groups work cooperatively so that the database and its annual updates work seamlessly with a wide range of data analysis software packages and data collection instrumentation. ICDD's software developments focus on use and visualization of the database. Today, the ICDD has over 60 distributors/partners that allow the product to be available around the world. A close examination of the distributors reveals that they are the leading software developers and world leaders in the manufacture of x-ray diffraction, electron diffraction and x-ray fluorescence equipment. By working cooperatively rather than competitively, resources are streamlined and the products are widely available for the benefit of the global community of scientists.
2. Why can't we have the database for free?
The ICDD has been self supporting for decades as a non-profit company. Proceeds from the sale of the PDF go into the constant maintenance and development of the database. New materials are being produced around the globe on a continuous basis. Through its strategic collaborations and grant-in-aid process, the ICDD is also collecting and editing this data on an annual basis. The database products are produced in book form, paper indexes and manuals, as well as CD-ROM products. Collecting, collating, publishing and distributing this data globally requires money. There is a very clear and direct relationship between the price of the database and the quality and functionality of the resulting product and the number of global x-ray analysis laboratories which purchase the database (sales volume). Income generated from the sale of the database allows the ICDD to have a continuous data collection, editorial, and publication effort that results in dynamic growth and continuous improvement.
Technology changes so rapidly that a stagnant database is usually doomed to failure. During the history of the ICDD, the database has changed from hand written cards to typed cards, books, keypunched cards, VAX tapes, CD-ROMS and DVD's and the self supporting finances of the ICDD has permitted transitioning the product to new formats and the annual database production and upgrades for six decades. Our latest efforts involved the transition of the database to a relational database, creation of a new organics database, enhancement of the metals and alloys subfile and a very large duplicate review editorial project. These editorial efforts often encompass years of work by dedicated teams of scientists, including many volunteers, to produce a product.
3. We have had several questions relating to speed of service - specifically the 3-4 months for publication of articles in Powder Diffraction and the request for regular downloads updates for the Powder Diffraction File.
In an electronic world speed is not only practical but highly desirable. The issue that we regularly face is not one of technical capability but of financial capability. High speed publication and distribution services are costly as well as the cost for people resources required for regular maintenance and implementation. The ICDD Board of Directors and staff members routinely weigh the cost of these services versus the benefits. In many instances we implement a slower process if it results in a lower price of the product to our members. Specifically in the case of Powder Diffraction we decided to go forward and pay the expense for joint paper and electronic production but saved costs in many areas of electronic services and editing.
4. Why is the Powder Diffraction File available in different formats and which one is best for me?
The ICDD Board of Directors made a very deliberate decision to produce the Powder Diffraction File in three separate formats - Books, PDF-2 and PDF-4. Each format is targeted to a specific group of our users. Books and Indexes are targeted for libraries and small laboratories that don't have access to funds or computer automated systems. The PDF-2 was designed and developed to be used with automatic diffractometers. The PDF-4 was designed for frequent users, having an annual and automatic update system, full pattern simulation, and state of the art data mining capability.
5. How do I data mine with PDF-4?
The large amounts of data contained in this database are organized in a fashion to facilitate high speed data mining. All the products in the PDF-2 and PDF-4 families have self contained Help documentation that can guide novices and experts through the features of the database. The Help file is found on the top toolbar whenever the database is opened. The “Search” section describes the various options available to the user to query the database. Be sure to look at the “History” section, which is a means of combining multiple queries that allows a user to rapidly find critical data from a very large database.
There are several types of data in the database. In general, this includes chemical names and classifications, diffraction data, physical property data and bibliographic data. Not every field is filled for every material data set. In some cases, the data may not have been present from the original source or maybe the material was given a common name after the original reference. Authors and editors may not have been aware that a material was a detergent or used as a pharmaceutical ingredient (excipients) at the time of analysis. Prototype structures are frequently used in the metal and alloy and mineral literature, but less frequently identified and assigned for general inorganics, organics and organometallics. Subfile assignments are determined by ICDD scientific task groups that define the chemistry of the subfile and designate assignments. This is an imperfect task. As a result, subfiles are not all inclusive. For example, a material designated as an explosive means that an expert in the field has identified this material as being explosive, it does not mean that all the explosives in the PDF are contained in the explosives subfile. The ICDD has long standing editorial task teams for minerals, metals and alloys, ceramics and zeolites that have ensured that these subfile compilations are fairly extensive. Alternatively, newer subfiles on battery materials, ion conductors and semiconductors are fairly recent and have ongoing editorial growth and revision.
6. How do I report an error found in the PDF? or Your data is wrong why don't you fix it!
The data in the PDF is extensively reviewed and analyzed prior to publication. All the numerical data is checked for self consistency by an extensive series of automated data checks. However, there is a large amount of data that is non-numerical (i.e. authors name, chemical names) where spelling or transcription errors can easily occur. Chemical formula are particularly susceptible, especially if the authors did not perform extensive chemical analyses.
Any errors can be reported to Terry Kahmer - firstname.lastname@example.org.
The editorial staff rapidly reviews any reported errors and fixes them. Corrected data will be typically reported in the next product release. If the error is numerical in nature, the data set will be reanalyzed by the ICDD's automated data analysis system. This ensures that the corrected data is consistent with other data entries in the data set. For example, a change in empirical formula would be analyzed relative to the calculated and experimental densities. A change in d-spacing would be compared to a refined unit cell parameter and proper indexing assignments for the lattice planes.
We frequently receive comments that items such as space group assignments, empirical formula, prototype assignments, mineral names and mineral classification are in error. These items are defined by specific editorial conventions. The Help documentation in our database products and Preface descriptions in our books and index manuals typically describe the conventions used for these products. Some reported errors, upon review, are actually differences between conventions used by the questioning scientist and the conventions used for the database construction.
If the suggested correction is a difference of opinion in convention or worsens the statistical analysis and self-consistency of the dataset, the suggested correction will not be implemented.
7. Why do you not sponsor a Denver X-Ray Conference in other parts of the world?
The ICDD has been a frequent financial supporter and technical contributor for the following global events dedicated to x-ray analysis. Technical contributions include invited speakers, workshops, and clinics.
SARX - Seminario Latino-Amercano de Analisespor Technicas de Raios
AXAA - Australian X-Ray Analysis Association
EPDIC - European Powder Diffraction Conference
Chinese National Conference on X-ray Diffraction
ICXRI - International Conference On X-Rays And Related Techniques In Research And Industry
ICDD members are frequently joint members of other scientific bodies that sponsor meetings in x-ray analysis. The ICDD regional technical co-chairs coordinate ICDD's participation in regional events around the globe. In addition to the venues mentioned above, the ICDD frequently supports regional crystallographic, material science and materials characterization forums as well. In the last two years, the ICDD held a workshop or clinic on every continent of the world with the exception of Antarctica.
8. I am looking for a software that will help me to get a quantitative analysis for XRD data. I am producing a powder that contains many phases and I want to know the composition of each phase that could be present. Is there any software that can do that for me?
There has been astounding progress over the last 10 years in automated high speed quantitative analysis. Modern equipment and software can rapidly identify complex multicomponent mixtures and quantitate the phases. There are a number of diffraction equipment manufacturers (both X-ray and electron) and software development companies that offer integrated data analysis packages. The best way to evaluate the various capabilities of this software is to attend one of the major powder diffraction conferences given around the world (i.e. AXAA, DXC, EPDIC, SARX etc.) and examine their software packages. In North America, the Denver X-Ray Conference (http://www.dxcicdd.com/) includes the world's largest annual exhibit of diffraction hardware and software.
All major equipment manufacturers and many independent software developers have integrated quantitation software using one or more of the methods described above. The ccp14 website run by the IUCr (http://www.ccp14.ac.uk/) contains free downloadable shareware programs. You would need to go to the site and click under the heading "Download Programs - What do you want to do" and then scroll down to the section entitled "Powder Diffraction Software". You will see programs that contain "Rietveld refinement" or "whole pattern fitting" that can be used to do total pattern analysis and quantitative analysis by Rietveld refinement. If you have the money, I would strongly recommend evaluating vendor programs since these are designed to be user friendly and are typically integrated with data collection and phase identification which may save you enormous amounts of time versus trying to understand and use a shareware program. You can check out several of the vendors software, either directly or through the distributor pages, on the icdd web pages (http://www.icdd.com/products/vendors.htm). If you review these websites and pages - you will unfortunately observe that few people call the programs quantitative analysis, instead they often refer to pattern fitting or Rietveld refinement. You would have to check that the version that you obtain is able to handle and quantitate complex mixtures.
You may also consider attending ICDD's X-ray Clinic (http://www.icdd.com/education/clinics.htm) that focuses on phase identification techniques. We typically spend 1-2 days on quantitative analysis reviewing the methods and teaching the fundamental assumptions used in each technique.