KINETIC PHOTOCHEMICAL AND PHOTOVOLTAIC ENERGY CONVERSION MODELS

Abstract— An energy conversion model descending from, and generalising, models due to BjoUrn, Calvin, Knox. Ross and others has been developed. It uses three sets of levels between which radiative, non-radiative and storage transitions are possible. Maximisation of the rate of power storage with respect to the absorption threshold yields wavelengths of the order of 680 nm is in good agreement with the absorption peak of chlorophyll a. Departure from the experimental spectra, for example by the substitution of equivalent black-body spectra, and passage to two sets of levels only, tends to destroy this agreement, which presents chlorophyll a as a materia! optimised through evolution for a maximum rate of power storage in day light. Various meteorological conditions are considered. The results found are not very sensitive to cloud cover. The simplified model for two sets of levels yields an interpretation in terms of transition probabilities of the parameters which occur in the simple solar cell theory. Both types of conversion are thus covered by the same theory. The model is also general enough to deal with photochemical or photovoltaic conversion in undersea conditions.