Natural ortho-para conversion rate in liquid and gaseous hydrogen

  title={Natural ortho-para conversion rate in liquid and gaseous hydrogen},
  author={Yu.Ya. Milenko and R. M. Sibileva and Mikhail A. Strzhemechny},
  journal={Journal of Low Temperature Physics},
We measured natural ortho-para conversion rates within a wide region of hydrogen fluid states: at temperatures 17–32 K in the liquid and at temperatures 40–120 K in the gas for densities up to 0.09 g/cm3. The experimental data for the gas phase are interpreted within the framework of a theory, the basic distinction of which from Wigner’s approach is that we take into account the dependence of the closest distance in a collision of two orthomolecules on their velocity (i.e., temperature). Our… 

A study of spin isomer conversion kinetics in supercritical fluid hydrogen for cryogenic fuel storage technologies

A detailed kinetic study of para-ortho hydrogen conversion under supercritical conditions using rotational Raman scattering is presented. Isochoric measurements of initially low ortho concentrations

Intensity of Raman modes as a temperature gauge in fluid hydrogen and deuterium

The Raman spectra of liquid H 2 ( D 2 ) have been collected in diamond anvil cell as a function of temperature at 3 GPa covering the range from 80 to ∼ 1000 K. Temperatures were measured using two

Mechanism of nuclear spin initiated para-H2 to ortho-H2 conversion.

A quantitative explanation for a diamagnetic ortho/para H2 conversion is given, based on the quantum-mechanical density matrix formalism originally developed by Alexander and Binsch for studies of exchange processes in NMR spectra.

Phase Transition of H2 in Subnanometer Pores Observed at 75 K.

A phase transition in H2 adsorbed in a locally graphitic Saran carbon with subnanometer pores 0.65 nm in width is reported, in which two layers of hydrogen can just barely squeeze, provided they pack tightly, and the increase in density with temperature is attributed to the fact that the oblong ortho-H2 can pack more densely.

Design of a Cryostat for Spectroscopic Investigation of All Hydrogen Isotopologues in the Solid, Liquid, and Gaseous Phases

Abstract A crucial part of the closed fuel cycle of future fusion power plants will be isotope separation, which takes place in a cryogenic distillation refraction column, where all six hydrogen



Theory of the Ortho-Para Conversion in Solid Hydrogen

The rate of ortho-para conversion in solid hydrogen (H 2 ) is calculated taking two kinds of interactions between ortho-molecules into consideration: interaction between the nuclear spins of one

The Vapor Pressures and Derived Thermal Properties of Hydrogen and Deuterium

(1) The vapor pressure equations of liquid and solid, normal deuterium were determined by comparison of the vapor pressure of deuterium with that of liquid, normal hydrogen between 13.9° and 20.40°K.

The solid molecular hydrogens in the condensed phase: Fundamentals and static properties

The molecular hydrogens (${\mathrm{H}}_{2}$, ${\mathrm{D}}_{2}$, HD, etc.) form the simplest of all molecular solids. The combination of the light mass, small moment of inertia, weak interactions,

The Rate of Evaporation of Liquid Hydrogen Due to the Ortho‐Para Hydrogen Conversion

The evaporation of liquid hydrogen caused by the heat of reaction of the ortho‐para conversion has been measured as a function of the o‐hydrogen concentration. The results are discussed, and a set of

Physics of cryocrystals

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