Using Slow Measurement Systems to Measure Fast Excited‐State Kinetics with Nonlinear Rate‐Competitive Optical Bleaching
AIP Conference Proceedings: Photoacoustic and Photothermal Phenomena
F. Scudieri and M. Bertolotti
The laser sources used in photothermal spectroscopy of homogeneous samples often have irradiances in excess of those required for singlet and triplet state optical bleaching of organic and biologically important molecules. These dynamic, nonlinear effects affect photothermal signal magnitudes in different ways, depending on the method used to detect the temperature change. In any case, signal magnitudes obtained at high irradiance and/or energy do not reflect the “small signal” absorbance, and apparatus calibration must take into account the change in effective absorption coefficient as a function of excitation irradiance and/or energy. This paper will present experimental methods for measuring nonlinear effects, methods and considerations for calibration for analytical measurement, and progress made towards interpretation of the nonlinear data in terms of the photophysics and excited state relaxation dynamics of the condensed phase species under study.
Using Slow Measurement Systems to Measure Fast Excited‐State Kinetics with Nonlinear Rate‐ Competitive Optical Bleaching Stephen E. Bialkowski and Agnès Chartier Photoacoustic and Photothermal Phenomena, F. Scudieri and M. Bertolotti, Ed. AIP Conference Proceedings 463 14‐17 1999