Electron-spin resonance, nuclear polarization, and spin relaxation of spin-polarized atomic hydrogen

Electron-spin-resonance measurements of spin-polarized hydrogen are presented. Excellent signal-to-noise ratio, previously obtainable only in pressure studies, allows quantitative fits to the separate a and b (proton up and down) decays of the nuclear-spin-polarized samples, yielding separate temperature dependences of the recombination rate constants Kaa and Kab. Spin relaxation due to magnetic particles in the substrate is studied for different thicknesses of solid H2 wall coating, and the results are compared with a new theoretical model.