منابع مشابه
Coordination nano-space as stage of hydrogen ortho–para conversion
The ability to design and control properties of nano-sized space in porous coordination polymers (PCPs) would provide us with an ideal stage for fascinating physical and chemical phenomena. We found an interconversion of nuclear-spin isomers for hydrogen molecule H2 adsorbed in a Hofmann-type PCP, {Fe(pz)[Pd(CN)4]} (pz=pyrazine), by the temperature dependence of Raman spectra. The ortho (o)-par...
متن کاملOrientational Ordering in Monolayers of Ortho-para Hydrogen
We discuss orientational ordering in monolayers of solid hydrogen in view of recent experimental findings in NMR studies of (ortho)c-(para)1−c-hydrogen mixtures on boron nitride substrate. Analysis of the temperature-concentration behavior for the observed NMR frequency splitting is given on the basis of a two-dimension (J = 1)c-(J = 0)1−c-rotor model with the quadrupolar coupling constant Γ0 =...
متن کاملNew ortho-para conversion mechanism in dense solid hydrogen.
Analysis of recent measurements of striking changes in the rate of ortho-para conversion of solid H(2) up to 58 GPa shows that the conversion mechanism must differ from that at ambient pressure. A new conversion mechanism is identified in which the emerging excitations are coupled to the converting molecules via electric quadrupole-quadrupole rather than nuclear spin-spin interactions. The latt...
متن کاملSeparating para and ortho water.
Water exists as two nuclear-spin isomers, para and ortho, determined by the overall spin of its two hydrogen nuclei. For isolated water molecules, the conversion between these isomers is forbidden and they act as different molecular species. Yet, these species are not readily separated, and no pure para sample has been produced. Accordingly, little is known about their specific physical and che...
متن کاملThe ortho and para fractions of molecular hydrogen in protostellar outflows and Herbig-Haro objects
Hydrogen molecules exist in two forms, according to the alignment of the nuclear spins. We present an accurate method for extracting the distributions of the two forms from three K-band infrared transitions. Images of the 1-0 S(0), S(1) and S(2) emission lines yield the ortho and para spatial distributions with negligible extinction and model dependence. The ortho-para ratio from individual poi...
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ژورنال
عنوان ژورنال: TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan)
سال: 1969
ISSN: 0389-2441,1880-0408
DOI: 10.2221/jcsj.4.114