Materials data

• Materials Science databases are similar to Process Chemistry databases in that they typically contain relatively large amounts of data about relatively few molecular entities. Also, they are often of high economic importance and are generally used in the engineering disciplines. Unlike process chemistry data, materials data is mainly concerned with entity properties rather than relationships between entities.

• An example of a Materials Science database is the OpticalConstants database developed and maintained by Maracas/ASU/DARPA. This database contains optical data (real and imaginary parts of the dielectric constant at various wavelengths) for just a few chemical entities: AlAs, GaAs and various AlGaAs crystals. It is used by people who want to monitor and control growth of semiconductors (mainly semiconductor designers) and is publically available as "ftp://149.169.38.2/maracas/OpticalConstants/".

• Like many Materials Science databases, OpticalConstants is useful only to those who already know it exists and already know (or can deduce) its format. It can't be found with standard search engines such as Alta Vista (e.g., the search query +AlGaAs "optical constants" returns 5232 matches, but the OpticalConstants database isn't among them). As valuable as the this information is, it lives in an almost completely isolated information universe.

• There are few (if any) theoretical difficulties in integrating most Materials Science databases with mainstream chemical information. Does the fact that this is rarely done argue a lack of motivation?

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