parahydrogen


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parahydrogen

[¦par·ə′hī·drə·jən]
(atomic physics)
Those states of hydrogen molecules in which the spins of the two nuclei are antiparallel; known as spin isomers.
References in periodicals archive ?
Unfortunately, one can also see from the figure that regardless of position under the lower parahydrogen moderator, the flux available for UCN production is very limited.
In principle this reopens opportunity for installing a moderator below the target of a completely different type than the upper flat parahydrogen moderator.
The EOS is explicit in Helmholtz energy and is valid for temperatures from the triple points (13.8033 K for parahydrogen, 13.957 K for normal hydrogen, and 14.008 K for orthohydrogen) to 1000 K and for pressures up to 2000 MPa, and the extrapolation appears to be well behaved at much higher values.
Research in this area will investigate properties of hydrogen-natural gas mixtures, various mixtures of orthohydrogen and parahydrogen, and the properties of hydrogen-methane mixtures pertaining primarily to storage, transmission and distribution applications.
Fundamental Equations of State for Parahydrogen, Normal Hydrogen and Orthohydrogen.
New equations of state have been developed in the Master's Thesis of Jacob Leachman (4) for normal hydrogen, parahydrogen, and orthohydrogen; these equations will be fully documented elsewhere (5).
Leachman, Fundamental Equations of State for Parahydrogen, Normal Hydrogen, and Orthohydrogen, Master's Thesis, University of Idaho, Moscow (2007).
In parahydrogen, the spins of the two protons point in opposite directions.
Using the vector meson exchange model of the weak nucleon-nucleon interaction developed by DDH and a model dependent representation of the strong interaction, Avishai and Grange calculated the neutron spin rotation through a liquid parahydrogen target and obtained [3]
There are two states of the hydrogen molecule, [H.sub.2], depending on the relative alignment of the proton spins: the spin 1 ortho-hydrogen and the spin 0 parahydrogen configurations.
Significant changes to the spin rotation polarimeter from the helium apparatus include: 1) a new cryostat appropriate for a 20[degrees] liquid parahydrogen including important safety features, 2) an upgraded position sensitive detector and 3) a change in [pi]-coil running conditions from static to dynamic.