MULTIPHOTON PROCESSES PROMOTED BY CONCENTRATED SOLAR ENERGY

ADVANCED SOLAR COLLECTOR TECHNOLOGY CAN PROVIDE LIGHT INTENSITIES SEVERAL THOUSAND TIMES THAT OF INCOMING SUNLIGHT. ACHIEVEMENT OF SUCH INTENSITIES SUGGESTS A NOVEL OPPORTUNITY: PROMOTION OF MULTIPHOTON CHEMICAL PROCESSES BY SOLAR SOURCES. AT VERY HIGH LIGHT INTENSITIES, MORE THANONE QUANTUM OF RADIATION CAN BE ABSORBED BY A SINGLE MOLECULE. THE RESULTANT MULTIPHOTON ABSORPTION CAN LEAD TO NEW PHOTOCHEMICAL REACTION PATHWAYS FOR CHEMICAL SYNTHESIS, AND TO MORE COMPLETE USE OF THE SOLAR SPECTRUM BY ENERGY STORAGE REACTIONS. IT IS INTENDED TO STUDY THE FEASIBILITY OF USING EXISTING SOLAR COLLECTOR TECHNOLOGY TO PROVIDE A NEW RADIATION SOURCE FOR MULTIPHOTON PROCESSES, PARTICULARLY IN THE GAS PHASE. THIS WILL BE AN EXPERIMENTALSTUDY IN THE LABORATORY USING SOLAR SIMULATORS. SEVERAL MODEL CHEMICAL SYSTEMS WILL BE SUBJECTED TO INTENSE NEAR-INFRARED RADIATION AND ANALYZED FOR MULTIPHOTON REACTIVITY. CANDIDATE MODEL SYSTEMS WILL INCLUDE UP-CONVERSION OF SATURATED HYDROCARBONS TO UNSATURATES AND HYDROGEN, ISOMERIZATION OF NORBORNADIENE TO QUADRICYCLANE, AND ALCOHOL DECOMPOSITION. IF MULTIPHOTON REACTIVITY IS ACHIEVED, THE MOLECULAR REACTION MECHANISM WILL BE STUDIED. BASED ON ESTABLISHED PHOTOPHYSICAL PRINCIPLES, THE INITIAL PREDICTION IS A TANDEM MECHANISM: SINGLE-PHOTON EXCITATION OF VIBRATIONAL OVERTONE AND COMBINATION TRANSITIONS, FOLLOWED BY MULTIPHOTON POPULATION OF THE VIBRATIONAL QUASI-CONTINUUM. THIS WILL BE DIAGNOSED BY RAPID INFRARED TRANSMISSION SPECTROSCOPY WITH TANDEM LASER AND INFRARED SOURCES. PHASE II RESEARCH WILL UTILIZE ACTUAL CONCENTRATED SOLAR RADIATION TO INVESTIGATE COMMERCIAL OPPORTUNITIES AND MORE THOROUGHLY CHARACTERIZE THE PHENOMENON.