title: Pressure-enhanced ortho-para conversion in solid hydrogen up to 58 GPa.
abstract: We measured the ortho-para conversion rate in solid hydrogen by using Raman scattering in a diamond-anvil cell, extending previous measurements by a factor of 60 in pressure. We confirm previous experiments that suggested a decrease in the conversion rate above about 0.5 GPa. We observe a distinct minimum at 3 GPa followed by a drastic increase in the conversion rate to our maximum pressure of 58 GPa. This pressure enhancement of conversion is not predicted by previous theoretical treatments and must be due to a new conversion pathway.
authors.affiliation: Department of Physics, Colorado School of Mines, Golden, CO 80401, USA.
authors.forename: J H
authors.initials: JH
authors.lastname: Eggert
authors.forename: E
authors.initials: E
authors.lastname: Karmon
authors.forename: R J
authors.initials: RJ
authors.lastname: Hemley
authors.forename: A
authors.initials: A
authors.lastname: Mao
authors.forename: A F
authors.initials: AF
authors.lastname: Goncharov