TIME-RESOLVED PHOTOACOUSTIC SPECTROSCOPY: THE PICOSECOND REGIME

Photoacoustic methods are applied to the detection and characterization of short-lived intermediates. Accurate kinetic data are obtained, with time resolution limited by the 25 spec laser pulse width. The inherent sensitivity of photoacoustic detection permits the study of dilute solutions and weakly-absorbing intermediates not accessible to conventional methods. Strongly fluorescent species, difficult to observe in simple transient absorption experiments, may be studied without difficulty; stimulated omission in laser dyes can be observed directly. The method also provides a convenient method for the characterization of picosecond and sub-picosecond laser pulses