Friday, March 6, 2015

Dynamic nuclear polarization of high-density atomic hydrogen in solid mixtures of molecular hydrogen isotopes

If you are interested in this article, you should also have a look at this article by Can et al., describing the Overhauser Effect in insulating solids:


http://blog.bridge12.com/2014/09/overhauser-effects-in-insulating-solids.html




Sheludiakov, S., et al., Dynamic nuclear polarization of high-density atomic hydrogen in solid mixtures of molecular hydrogen isotopes. Phys Rev Lett, 2014. 113(26): p. 265303.


We report on magnetic resonance studies of high-density atomic hydrogen and deuterium in solid hydrogen matrices at temperatures below 1 K. Average concentrations of H atoms approximately 3x10^{19} cm^{-3} are obtained in chemical tunneling reactions of isotope exchange with D atoms. The products of these reactions are closely located pairs of H atoms near D_{2} molecules with strong exchange interactions. We discovered a dynamic nuclear polarization effect on H atoms created by pumping the center of the H electron spin resonance spectrum, similar to the Overhauser effect in metals. Our results indicate that H atoms may be arranged inside molecular matrices at separations equivalent to local concentrations of 2.6x10^{21} cm^{-3}. This opens up a way to build a metallic state of atomic hydrogen at zero pressure.