Thermal conductivity of solid hydrogen with ortho-hydrogen concentrations between 20 and 70 at.%

Abstract

We have measured the thermal conductivity of solid hydrogen in the temperature range of 1.4-13 K. Measurements were taken on a single sample over a 196-h period. During this time the ortho-hydrogen concentration changed from 75 to 19.8 at.%. Because precise temperature control allowed corrections to be made for changing ortho concentration, thermal conductivity versus temperature is given for constant ortho-hydrogen concentrations of 20, 30, 40, 50, 60, and 70 at.%. Addition of thermal resistances was assumed and several curve fits to the data are given, including one with terms proportional to ${c}^{2}{T}^{\ensuremath{-}2}$ and $c{T}^{\ensuremath{-}3}$. An umklapp term is given that also agrees well with the data from previous experiments.