Chemical instabilities in closed systems with illumination

The authors study closed chemical reaction systems with illumination and show theoretically, on an autocatalytic reaction model and a substrate-inhibited enzyme reaction model, that if a photochemical reaction may transform some of the products of the reactions in the mechanism into reactants, the closed system may give rise to chemical instabilities, including multiple stationary states and oscillations, under both isothermal and nonisothermal conditions. The essential points in the occurrence of these chemical instabilities are the positive feedback provided by the autocatalytic reaction or substrate inhibition and the displacement of the system far from equilibrium by the photochemical reactions. There are functional similarities between the closed, illuminated systems and open systems (continuous stirred tank reactor, CSTR). Experimental verification of such chemical instabilities in a closed, illuminated system remains to be shown; but the theoretical possibility shown here opens the way to convert radiation energy of the light directly into mechanical energy, in isothermal systems with variable volume and nonisothermal systems at constant volume.