Light absorption, molecular

The absorption of radiation produces unstable species. Flash photolysis does so by interaction of light with a solute. The transient may be a photoexcited state or a molecular fragment. Pulse radiolysis starts with highly reactive entities formed by dissociation of the solvent (e.g., H, eaq, and HO from H20) and consists of a study of their reactions or of reactive transients derived from them. In either case one monitors the ensuing reactions by luminescence (for excited states), light absorption, or conductivity changes. 

The potential value of the application of molecular orbital methods in colour chemistry is immense. In essence, the reason for this is that the methods enable, in principle, many of the light absorption properties of dyes, from a knowledge of their chemical structure, to be calculated with the aid of a computer. Thus, the colour properties of any dye whose structure may be drawn on paper may be predicted, with some expectation of accuracy, without the need to resort to devising a method for the... 

Molecular excitation by light absorption takes place during the period of one vibration of the exciting light wave. For light with a wavelength A equal to 300 nanometers (nm), this corresponds to 10"15 sec ... 

Phosphates seem to be the most likely compounds for moderating the process between light absorption and chemical, energy-consuming molecular conversions. 

The coefficient of infrared light absorption by an adsorbed molecular monolayer of the surface concentration N/F depends both on the angle of incidence reckoned from a normal to the surface and on the effective absorption cross-section o(ft>) 122... 

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