Beyond the Beer-Lambert law: The dependence of absorbance on time in photochemistry
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- 作者：J. Mark Parnis ; Keith B. Oldham
- 关键词：Absorbance ; Photochemical laws ; Beer&ndash ; Lambert law ; Photodegradation ; Mixing ; Quantum yield
- 刊名：Journal of Photochemistry and Photobiology A: Chemistry
- 出版年：2013
- 出版时间：1 September, 2013
- 年：2013
- 卷：267
- 期：Complete
- 页码：6-10
- 全文大小：396 K
文摘
The photochemical law governing chemical conversion of a photoactive species is derived and solved analytically. In the absence of solution mixing, the law predicts a remarkable symmetry in which the dependence of light intensity on distance matches the dependence of concentration on time. An exact method is described whereby a time sequence of experimental transmittance/absorbance data obtained during a light-induced chemical process can provide a value of the quantum yield for the photoreaction. It is demonstrated that this procedure is not invalidated by solution mixing.