@article {Fiamingo:1985-01-01T00:00:00:0003-7028:116,
author = "Fiamingo, Frank G. and Alben, James O.",
title = "Photochemical Dissociation in Optically Dense Solutions: Applications to Photolyzed Carboxymyoglobin (Mb⋆CO)",
journal = "Applied Spectroscopy",
volume = "39",
number = "1",
year = "1985-01-01T00:00:00",
abstract = "Photodissociation of ligands has made important contributions to the understanding of function and structure of heme proteins. Here we present a theory for photochemical dissociation that is not limited by the assumption of previous analyses of optically thin samples, and apply it to
interpretation of the photodissociated state of carboxymyoglobin (Mb⋆CO). Equations are derived and presented in terms of the effects of absorbance, [log_{10}(*I*
_{0}/*I*) = *A*, the probability of absorption of light quanta per unit surface area], and
the potential for dissociation, *D* (maximum probability of photodissociation per unit surface area; a linear function in time of photolysis), for both monochromatic and polychromatic light sources. When monochromatic light is used, we show that for large absorbances (*A* > 2)
the fractional photolysis increases as (log *D*)/*A*, and may appear to "saturate" even though well below completion. For polychromatic light intensities and absorbances, the theory predicts that the near-infrared tail of the absorbance band of carboxymyoglobin should be sufficiently
transparent to allow the radiation to penetrate the sample, yet still have a significant absorptivity such that complete photodissociation is possible. An optically thick myoglobin-CO sample illuminated with a tungsten lamp was observed to behave somewhere between these two theories. These
theoretical relations may be useful in the analysis of photolysis data from optically dense solutions and as a guide for future experimental design.",
pages = "116-123",
url = "http://www.ingentaconnect.com/content/sas/sas/1985/00000039/00000001/art00022",
doi = "doi:10.1366/0003702854249367",
keyword = "Mathematical modeling, photolysis, Methods, analytical, Infrared, UV-Visible spectroscopy, Beer-Lambert relations, Techniques, spectroscopic, Quantum efficiency"
}