Upgrade of ESR Facility

The Department of Chemistry at Columbia University will use this award for the purchase of an upgrade for two electron spin resonance (ESR) spectrometers. Both instruments are capable of acquiring ESR spectra in steady state operation and in time-resolved ESR experiments. Fourier transform (FT) ESR methods will also be implemented. Both instruments will be equipped with lasers capable of providing nanosecond pulses for excitation of samples and the production of paramagnetic transients. The instruments will be used by members of the department for a wide range of work and will be used for a variety of state-of-the-art experiments including: 1) Gas phase experiments employing time resolved laser flash photolysis to investigate the possibility of employing circularly polarized light to produce electron spin polarization of reaction products; 2) Low temperature experiments which investigate the magnetic characteristics of novel materials; 3) Room temperature solution experiments which employ time resolved methods to investigate electron polarization transfer for organic triplet states and radicals in order to elucidate the mechanism of electron exchange between paramagnetic species; and 4) Low temperature electron spin echo envelope modulation (ESEEM) experiments to investigate photosynthetic reaction centers. %%% An electron spin resonance (ESR) spectrometer is an instrument used to obtain information about the molecular and electronic structure of molecules. It may also be used to obtain information about the lifetimes of free radicals which are often essential for the initiation of tumor growth and/or a variety of chemical reactions.