"The indexing terms listed in the thesaurus are those found in the RCDC Bibliographic Data Base and therefore are the terms used to generate the keyword index in this volume. The keywords are arranged alphabetically. Numbers, dashes, parentheses and super- and sub-scripts are ignored in ordering the terms except when required to distinguish two terms. Thus, '1-propanol' precedes '2-propanol' (following 'propane') and 'H2O+' precedes 'H2O-' and 'H2O2+' (all three precede 'hole'). Arrangement is word by word, thus 'hole traps' precedes 'holes'. The name of any element may be used as a keyword, but the names have been omitted from the listing. In addition, the following terms may be used: 1. 'element name' followed by a one- to three-digit number, specifying a nuclide, e.g. cobalt-60. 2. 'element name' followed by 'ions', e.g. vanadium ions. 3. 'element name' followed by 'compounds', e.g. nickel compounds. 4. 'element name' followed by 'atoms', e.g., oxygen atoms. None of the terms represented by 1 through 4 appear in the thesaurus with the exception of several in group 3 for which narrower terms have neen designated as keywords. Another exception occurs in the indexing of halogen, nitrogen and sulfur compounds; element symbols rather than element names have been used (Br, Cl, F, I, N, S) and the keywords appear as Br compounds, organic and Br compounds, inorganic, etc. Keywords which are the names of specific compounds or classes of compounds are used to define the primary subject of the investigation (or reactant). Products are indexed only by terms such as 'hydrogen formation', 'alkane formation', etc. The addition of -a or -s to a chemical name indicates that the compound was used as an additive or solvent, respectively. Thus, the keyword index may contain 'ethanol-s' as well as 'ethanol'. Each keyword entry contains a listing of broader (BT), narrower (NT) and related (RT) terms, as well as synonyms (see the USE and USED FOR (UF) terms). The narrower terms are always used when applicable, so to find all information on a particular keyword the narrower terms should also be consulted. This thesaurus was developed as a guide for the indexer and has been published to aid the users of the information services provided by the Radiation Chemistry Data Center."