Phase diagram for ortho-para-hydrogen monolayers

Physics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

Scientific paper

The phase diagram for orientational ordering of hydrogen monolayers on graphite and boron nitride is revised in view of current theory and experimental observations from nuclear magnetic resonance (NMR) studies recently reported for ortho-H2 concentrations 0.35 ≤ c ≤ 0.92 and temperatures 0.14 ≤ T ≤ 1.80 K. The characteristic interaction coupling Γ0 = 0.50 ± 0.03 K and the crystalline field amplitude V0 = 0.70 ± 0.10 K are derived from experimental data, and distinct types of the local orientationally ordered structures are analysed using a proposed model for site-diluted uniaxial quadrupoles on a triangular plane lattice of hexagonal symmetry. The long-range periodic pinwheel structure and the short-range quadrupolar glass (QG) phase are stable above the 2D site-percolation limit, cp = 0.72, and for 0.48 < c < cp, respectively, where quadrupolar-order effects dominate. At very low T, the QG phase shows instability with respect to local dipole-like polarization effects and the ground state changes to a hindered rotor state. Two para-rotational local ordered PRA and PRB structures driven, respectively, by positive and negative crystalline fields are well distinguished, experimentally and theoretically, and are rather different from the unique PR phase suggested earlier by Harris and Berlinsky.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Phase diagram for ortho-para-hydrogen monolayers does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Phase diagram for ortho-para-hydrogen monolayers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Phase diagram for ortho-para-hydrogen monolayers will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-1544340

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.