Preparation of personal bibliographies using a large computing facility.

Large modern computing facilities, which normally include text editing, sorting, and searching, are now available to most scientists. Such features are invaluable for a personal bibliography, which may be prepared according to the taste of the user. Our method requires only that the references be less than or equal to 120 or 240 characters (spaces) in length. The references may be written randomly, in which case searching is performed for retrieval, with some order, when searching and sorting may be used for retrieval, or with extensive order, when, in addition, indexes may be prepared by a single command. Two bibliographies with extensive order are described. Suggestions for starting a bibliography by those unfamiliar with computers are given in the Appendix.

Varioilluminator (subtractive double monochromator with variable bandpass).

A varioilluminator is a double monochromator in which the dispersion in the second half of the instrument is subtractive rather than additive and in which the central slit can be opened very wide. The wavelength bandpass depends almost entirely upon the width of the central slit. The jaws of the central slit in the instrument described here were made independently variable, so that the long and short wavelength cutoffs could be independently selected. Quartz or glass prisms could be used, and bandpasses from about 15A to several hundred Acould be chosen.

Apparatus for measurement of luminescence spectra with a digital recording system.

An apparatus is designed for use in obtaining fluorescence spectra, excitation spectra, and delayed fluorescence spectra, usually at low temperatures. A photometrically regulated 6500-W xenon lamp is used as excitation source, a double monochromator or varioilluminator as excitation monochromator; a variable temperature liquid helium cryostat as specimen holder; a double grating monochromator or varioilluminator as detection monochromator; and a photomultiplier as detector. A quartz-iodine lamp calibrated against a standard tungsten-quartz lamp is used for intensity calibrations. Fluorescence spectra are recorded by a digital system with a shaft position encoder for digitizing wavelength and an analog-to-digital converter for intensity. Data are recorded on magnetic tape which can be processed directly by an IBM system 360 computer. The selection of components of adequate resolution, speed, and capacity is discussed, and the computer programs are described. Installation of the recording system 1ms facilitated greater wavelength accuracy and long calculations on the experimental data. Examples are given.