In order to elucidate the photochemistry and photophysics of chemicals it is necessary to employ a wide variety of techniques e.g. fluorescence, phosphorescence, conventional and laser flash photolysis, luminescence and ESR. Because much of the equipment we need is not available commercially we have had to build much of it ourselves. Additionally we have interfaced most of our equipment to PC~s for ease of data acquisition and manipulation. Two old spectrophotofluorometers (steady state and phase modulation), have been combined into one T- configured unit which is gradually being upgraded. The new configuration combines the previous applications to acquire fluorescence and phosphorescence spectra, and to measure polarization and fluorescence and phosphorescence lifetimes. The steady-state singlet oxygen (1O2) spectrophotometer has been optimized; a new very efficient light- collimating cell compartment has been built. An efficient UV interference filter which blocks IR light scatter from the lamp allows the excitation of UV (270nm-370nm) absorbing samples. A new chopper for light modulation and a SpectraPro-275 Monochromator, together with a germanium diode and lock-in amplifier completes a very sensitive computer- controlled device. The laser flash photolysis spectrometer has been modified to include a flow system to enable us to refresh anaerobic samples after strong laser excitation which usually irreversibly bleaches the irradiated area. A singlet oxygen (lifetime) luminescence spectrometer has been built and tested. Noise-free signals from 1O2 phosphorescence decay are observable after single shot laser excitation. A prototype photoconductivity cell to measure electrical photoconductivity in dielectric liquids in conjunction with ESR detection is being built. This will be interfaced to the time-resolved apparatus to permit studies of systems that cannot be observed optically. The laser flash photolysis system will be upgraded using a tunable OPO laser system which emulates dye lasers. This new system will be adapted for EMF studies by incorporating an electromagnet.
