A method to improve the nonrepetitive acquisition of transient absorption spectra with an intensified charge-coupled device camera

This article describes in detail a new method of data acquisition using an intensified charge coupled device (CCD) camera coupled with a monochromator as a time-resolved absorption spectrometer. The method is based on a full image transfer taking full advantage of the dynamic range of the CCD. The accumulation of several lines of the matrix is then limited by the 32-bit range of the computer calculation. The absorbance characteristics are a good signal-to-noise ratio and a large linearity domain (absorbances between 0.05 and 0.6) in the visible range (350-700 nm) with temporal gates less than 100 ns. The time-resolved absorption spectra obtained for two transient species in aqueous solution [CO3- and (SCN)(2)(-)] are presented and are in good agreement with those considered as reference and obtained with a multistep method with a classical monochromator-photomultiplier device. (C) 1998 American Institute of Physics.