The time dependence of the de-excitation of the phosphorescent state of phenanthrene-d10 by radiationless energy transfer to the fluorescent state of rhodamine B is observed. Good agreement is found with predictions based on the long-range dipole—dipole interaction described by Förster.

The phosphorescence lifetimes of several aromatic hydrocarbons and their deuterated counterparts have been measured in plastic matrices as a function of temperature. The onset of a dark process at higher temperatures is generally observed and is believed to be a property associated with the aromatic molecule, rather than with some ``unknown'' quencher. Phonon involvement is suggested by the data. An apparatus for accurately measuring phosphorescence decay over seven half-lives with minimal noise is also described.

Members of a Subcommittee of the Society of Motion Picture and Television Engineers, with the cooperation of other professional societies, have developed specifications for an operational test pattern for evaluation of television monitors and film recording cameras used in medical diagnostic imaging. The purpose of this test pattern and the associated recommended practice is to provide the users of the medical diagnostic display systems with a comprehensive test for set-up, acceptance testing, and day-to-day operational checks. Details of the test pattern, examples of the system problems diagnosed by use of the pattern, and methods for optimizing display devices with the pattern are presented.

The beam from a Q-spoiled ruby laser is focused on a graphite block maintained under vacuum. The C2 Swan system is produced and the fluorescence decay time is interpreted as the lifetime of the A 3IIg state of C2. The lifetimes of four different vibronic levels of that state are measured. The variation of the electronic part of the transition moment over the nuclear coordinates is deduced from the spread of the lifetime values. The oscillator strength f(0, 0) for the Swan system is calculated to be (4.33±0.12) 10−3.

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