Quasi-photostationary states

P--CH2CH2COCT Fomaid and backward transformations were nearly quantitative conversion to the dimer at quasi-photostationary state at 4 C > 55 %. 

In the case in which the photoexcited pairs of electrons and holes are relatively stable so that thermal equilibrium is established between phonons and electrons in the conduction band as well as between phonons and holes in the valence band, we can define individually the electrodiemical potentials of photoexcited electrons and of holes in the photostationary state. Here, thermal equilibrium is not established between the photoexcited electrons in the conduction band and the holes in the valence band. The electrochemical potential, thus defined, for the photoexcited electrons and holes is caUed the quasi-Fermi level of electrons nCp, and the quasi-Fermi level of holes,[Schockley, 1950 Gerischer, 1990]. 

See [29] [30] for the structures of the various components in the over-irradiation mixtures. Since 5 is also converted to a secondary photoproduct on prolonged UV irradiation, the above-mentioned mixture represents not a photostationary state but a quasi-photosta-tionary one. 

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