Temperature and Magnetic Field Dependence of Three-Body Recombination in Spin-Polarized Hydrogen

Abstract

The three-body recombination rate in spin-polarized hydrogen has been measured at temperatures from 0.25 to 0.60 K in magnetic fields from 5 to 9 T. In contrast to theoretical expectation, the three-body rate is a weakly decreasing function of field in this region. At 7.6 T the gas and surface three-body rate constants are ${L}_{g}=7.5(3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}39}$ ${\mathrm{cm}}^{6}$ ${\mathrm{s}}^{\ensuremath{-}1}$ and ${L}_{s}=2.0(6)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}24}$ ${\mathrm{cm}}^{4}$ ${\mathrm{s}}^{\ensuremath{-}1}$. The large value of ${L}_{s}$ can account for effects previously attributed to an anomalously large surface two-body nuclear relaxation rate.