title: Optimization of 1H spin density for dynamic nuclear polarization using photo-excited triplet electron spins.
abstract: In dynamic nuclear polarization (DNP) using photo-excited triplet electron spins, known as Microwave-Induced Optical Nuclear Polarization (MIONP), the attainable (1)H polarization is determined by the ratio of the buildup rate and the spin-lattice relaxation rate, in turn depend on the (1)H spin density. It is shown that the final (1)H polarization can be enhanced by diluting the (1)H spins with partial deuteration. The DNP experiments are demonstrated in 0.05 mol% pentacene-doped p-terphenyl for various (1)H abundances. It is also shown that the (1)H spin diffusion coefficient can be determined by examining the initial buildup rate of (1)H polarization for various repetition rates of the DNP sequence.
authors.affiliation: Division of Advanced Electronics and Optical Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyamcho, Toyonaka, Osaka 560-8531, Japan. kagawa@qc.ee.es.osaka-u.ac.jp
authors.forename: Akinori
authors.initials: A
authors.lastname: Kagawa
authors.forename: Yu
authors.initials: Y
authors.lastname: Murokawa
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Takeda
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kitagawa
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D017785:Photons; D011522:Protons; D013113:Spin Labels; D013730:Terphenyl Compounds / Q000737:chemistry* / Q000528:radiation effects*
chemical_list: D011522:Protons; D013113:Spin Labels; D013730:Terphenyl Compounds