Modulated Optical Null Spectrophotometer for Flash Excitation Reactions

Abstract
A differential flash-photolysis kinetic spectrophotometer has been developed for studies of photo-induced reactions. The instrument system has a response time of 1.4 msec and an average differential sensitivity of 0.004 OD in the 400–700 nm region. A modulated monochromatic source and phase-lock detection are employed for signal-to-noise enhancement. The maximum actinic flash input is 360 J.