NANOSECOND TRANSIENT ABSORPTION-SPECTROSCOPY

Biomolecules have been investigated by a number of techniques, including resonance spectroscopy, nuclear magnetic spectroscopy (NMR), electron spin resonance (ESR); structural analysis X-ray crystallography, diffraction, and extended X-ray absorption fine structure (EXAFS); and various other spectroscopic methods. The information obtained from these studies generally pertains to the structural signatures of the molecules. However, these techniques are limited in their ability to monitor such fast events as structural changes, bond formation or cleavage, and reaction kinetics that are important to a basic understanding of reaction mechanisms. One advantage of fast spectroscopy is that transient spectral data may identify a variety of mechanistically significant structural intermediates that cannot be detected with steady-state spectroscopy, and may provide information on their temporal evolution as well. This chapter describes the instrumentation necessary to develop an optimal system that measures transients on a nanosecond time scale. Because numerous systems are available, this chapter discusses the frequently used components of the various nanosecond absorption configurations. The setup of one particular system is also described. The chapter also presents some of the different applications of nanosecond absorption techniques. © 1993, Academic Press, Inc.