Molecular hydrogen isotopes adsorbed on krypton-preplated graphite: Quantum Monte Carlo simulations

Adsorption of ortho-deuterium and para-hydrogen films on a graphite substrate, pre-plated with a single atomic layer of krypton, is studied theoretically by means of quantum Monte Carlo simulations at low temperature. Our model explicitly includes substrate corrugation. Energetic and structural properties of these adsorbed films are computed for a range of hydrogen coverages. Thermodynamically stable adsorbed films are solid, with no clear evidence of any liquid-like phase. Quantum exchanges of ortho-deuterium and para-hydrogen are essentially absent in this system, down to zero temperature; consequently, this system displays no superfluidity in this limit. Our simulations provide evidence of a stable domain wall fluid at low temperature, consistently with recent experimental observations.Comment: 7 pages, 7 figure

Due Process Hearing Officers: Characteristics, Needs, and Appointment Criteria

This is the publisher's version, also found here: http://sped.org/Characteristics and training needs of due process hearing officers in North Carolina were surveyed. It was found that current regulations governing appointments of hearing officers are insufficient to ensure appointment of qualified and impartial persons. Criteria were analyzed and suggestions for training and appointments are made