NDRL Radiation Chemistry Data Center About the Data Compilations

The data

The continuing program of the Radiation Chemistry Data Center for the compilation of data has emphasized the collection and review of reaction rate data for transient radicals, radical ions and excited states in solution. The data largely results from the techniques of pulse radiolysis and flash photolysis and related methods which have produced a large body of kinetic data for chemical reactions occurring in less than about 10^-3 seconds. Compilations of this data have appeared in a series of refereed papers and reports. The data, including recent additions, is here made available to the scientific and technical community as a world wide web resource.

All of the data in this database is for chemical kinetics in solution. A comparable database for chemical kinetics in solution, for the most part the same data, is also maintained by NIST. A comparable database for chemical kinetics in the gas phase is also maintained by NIST.

The RCDC compilations on this web site are presented as individual groups of pages corresponding to each published work. Each compilation consists of an introductory article, describing the scope of the compilation, with the considerations and criteria for data evaluation discussed. Nomenclature for the compilation is also described here. For several compilations the introduction is followed by one or more pages of links organized as an index or table of contents to the individual pages of the compilation. These links allow the browsing of the data by species name. Each page tabulates the reaction of a transient species with a particular reactant.

For example, within the Buxton, Greenstock, Helman and Ross compilation on rate constants of transient water radicals, there are separate sections for hydrated electrons, hydrogen atoms, hydroxyl radicals, and oxide radical anions. Each page within a section contains the rate constant, conditions of measurement, and literature reference for the reaction of that transient with a given reactant (e.g., for hydroxyl radical, there are separate pages for methanol, ethanol, acetic acid, and hydroquinone). Some of the compilations are not arranged for browsing, and have no index page. For all works, except Reduction Potentials and Quantum Yields, access to the data pages may also be obtained using the compilation search feature (see below).

Most RCDC compilations on this web site may be searched using reactants as a search key. Capitalization and other punctuation is important, so the use of wildcard characters is helpful for these searches; a percent sign (%) or an asterisk (*) matches one or more characters, while an underscore (_) matches any single character. An example would be a search for methanol reacting with hydroxyl radical; in our database, the entry for a chemical entity is capitalized -- in this case, 'Methanol' is the indexed term. Therefore 'methanol' will not be found in such a search, while 'Methanol' or '_ethanol' will get the desired references. The search term '%ethanol' will retrieve the references to methanol, along with references to twenty other alcohols -- clearly, some care in the design of the search is required for best results! Using an appropriate wildcard search will enable one to determine the exact reactant name indexed in the database, resulting in a well-focussed answer set.

There are four distinct searches. First a search for reaction rate data that specifies two reactants, one of which is hydroxyl radical or hydrogen atom or hydrated electron or oxide radical anion or singlet oxygen. Second a search for reaction rate data that specifies any one reactant. Third a search only covering quenching of metal complexes. Fourth a search only covering triplet-triplet absorption spectra. The appropriate search is linked to each compilation in the above table.

E-mail: madden.1@nd.edu Author: K.P. Madden