In particular, one set of parameters

can describe the behaviour of the magnetic field dependence for high and low oxygen coverage of the sample by changing only the parameters directly relevant to the energy transfer process. This represents the first detailed and quantitative investigation of magnetic field effects in the photogeneration of singlet oxygen by use of silicon nanoparticles and provides a model which can easily be expanded in order to investigate the dependence of the energy transfer process on nanoparticle size, excitation intensity, and temperature; this work is in progress. Acknowledgements This work was supported by the Engineering and Physical Sciences Research Council (UK) under grant EP/J007552/1. References 1. Kovalev D, Gross E, Künzner N, Koch F, Timoshenko VY, Fujii M: Resonant electronic energy transfer from excitons confined BTSA1 clinical trial in silicon nanocrystals to oxygen

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