Phonon spectrum and density of states for commensurate monolayer phases of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">H</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>, HD, and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">D</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msu

Novaco, Anthony D.

doi:10.1103/physrevb.46.8178

Cited by 22 publications

(16 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the value for graphite is in good agreement with the energies per particle for this registered structure given by Novaco. 20 The approximate 2% difference can be ascribed to the slightly different Lennard-Jones parameters used in that work.…”

Section: Resultsmentioning

confidence: 87%

Phase diagram of D2adsorbed on graphene and graphite

Carbonell-Coronado

Gordillo

2012

Phys. Rev. B

View full text Add to dashboard Cite

The phase diagram of o-D 2 adsorbed on top of both graphene and graphite was calculated for T = 0 K using the diffusion Monte Carlo technique. Both diagrams were found to be virtually identical, except for the energy offset due to the presence of additional graphene sheets in graphite. The ground state of D 2 on graphene and graphite was a √ 3 × √ 3 commensurate structure that upon a pressure increase was transformed into a so-called γ phase, characterized by an oblique unit cell rotated a given angle with respect to the axis of the upper graphene sheet. At even higher densities, a triangular incommensurate structure similar to the one in the H 2 case is found. A δ commensurate phase at 0.0789Å −2 can barely be distinguished from the γ incommensurate solid at this density, but an commensurate structure at 0.0835Å −2 is more stable than its γ counterpart. Between the √ 3 × √ 3 structure and the γ solid, a striped domain wall α phase was found to be more stable than a mixture of both.

show abstract

Section: Resultsmentioning

confidence: 87%

Phase diagram of D2adsorbed on graphene and graphite

Carbonell-Coronado

Gordillo

2012

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…[33][34][35] On this surface the mean intermolecular H 2 -H 2 distance equal to 4.26 Å is substantially larger than on NaCl ͑3.96 Å͒ and than in the solid ͑3.79 Å͒. The molecule-surface distance equal to 2.79 Å at equilibrium is appreciably changed due to large amplitude zero point translational motions, since it becomes 2.96 Å and the free energy is around Ϫ47 meV.…”

Section: B Equilibrium Geometrymentioning

confidence: 80%

Monolayers of ortho-H2, para-H2, para-D2 and normal-H2 adsorbed on NaCl(001) single crystal surfaces

Heidberg

Voßberg

Hustedt

et al. 1999

The Journal of Chemical Physics

View full text Add to dashboard Cite

Articles you may be interested inThe structure of N2 adsorbed on the rumpled NaCl(100) surface-A combined LEED and DFT-D study J. Chem. Phys. 137, 174705 (2012); 10.1063/1.4764299The monolayer structure of CO 2 adsorbed on the NaCl(100) single crystal surface: A tensor low-energy electron diffraction analysis A two-dimensional quantum crystal: H 2 on NaCl (100) Experimental and theoretical studies of the monolayer structure of OCS adsorbed on NaCl(001): Coexistence of orientationally inequivalent phases Monolayers of pure ortho-H 2 , para-H 2 , para-D 2 and normal-H 2 adsorbed on NaCl͑001͒ single crystal surfaces were investigated at temperatures Tу10 K and pressures between 1ϫ10 Ϫ10 and 1ϫ10 Ϫ5 mbar by polarization Fourier transform infrared attenuated total internal reflection spectroscopy ͑PIRS-ATR͒. Single induced polarized infrared absorptions of the fundamental vibrational modes of pure (M ϭ͉1͉) ortho-H 2 and para-H 2 , as well as pure (M ϭ͉1͉) para-D 2 and, slightly shifted, in the mixture of normal-H 2 were observed, allowing definite assignments of each. With respect to the gas phase values, the wave numbers were measured to be redshifted by 32.0 and 28.0 cm Ϫ1 for pure (M ϭ͉1͉) ortho-H 2 and para-H 2 . In close agreement with potential calculations, these absorptions were assigned to H 2 molecules adsorbed on the cation sites of the large NaCl͑001͒ terraces, while neither the absorptions associated with H 2 adsorption above defects nor the absorptions of (M ϭ0) H 2 molecules above the anion sites, detected on microcrystallite surfaces at lower temperature, are observed under the conditions set. The present experiments corroborate the fact that the NaCl surface discriminates between the (M ϭ͉1͉) ortho-, (M ϭ0) ortho-and paraspecies. The lateral interactions have no influence on the stable sites and the discrimination, but they contribute by an additional shift of the peak frequencies of about 15%. Moreover, with polarized light, induced transition dipole moments perpendicular to the surface for ortho-H 2 , para-H 2 and para-D 2 were observed, while none parallel to the surface was detected. These results are in accordance with the calculations showing that the s-component of the polarization disappears due to free rotation of the H 2 (D 2 ) molecules in a plane parallel to the surface, while the p-component gives a maximum intensity. The integrated cross sections Ќ were measured and found to have the same order of magnitude: (6Ϯ3)ϫ10 Ϫ22 m/molecule for (M ϭ͉1͉) ortho-H 2 and (4Ϯ2)ϫ10 Ϫ22 m/molecule for para-H 2 within the error limits; the theoretical value is 4.5ϫ10 Ϫ22 m/molecule for both species. Applying the extended Langmuir equation, the difference between the desorption energies (E des ortho ϪE des para ) of (Mϭ͉1͉) ortho-H 2 and para-H 2 adsorbed on the ͑001͒ terraces of NaCl͑film͒ was determined to be 0.6Ϯ0.2 kJ/mol, in agreement with the calculated value ͑0.8 kJ/mol͒. Assuming that the sticking coefficients of (M ϭ͉1͉) ortho-H 2 and para-H 2 are not dependent on temperature between 17 and 30 K,...

show abstract

“…8,9,40 The quantum solids present well-known difficulties due to zero-point motion, 44 which have been addressed with self-consistent phonon theory in both 3D solids and monolayer films. 45,46 They are thus logical sequels to the present work.…”

Section: Discussion and Concluding Remarksmentioning

confidence: 96%

Phonons and specific heat of neon and methane on the surface of a nanotube bundle

2003

View full text Add to dashboard Cite

Adsorbed Ne and CH 4 on the external surface of a nanotube bundle form quasi-one-dimensional phases at low temperature. This paper presents a study of the phonon spectra and the specific heat associated with these phases. For Ne, two groove phases of different density are investigated, while for CH 4 two groove phases of different density and the ''three-stripe'' phase are studied. In addition, results from classical Monte Carlo simulations are presented which provide information about the thermodynamic behavior of different phases of CH 4 at higher temperatures; a dimensionality crossover is indicated by the presence of a distinctive peak in the specific heat.

show abstract

Phonon spectrum and density of states for commensurate monolayer phases ofH2, HD, andD2

Cited by 22 publications

References 56 publications

Phase diagram of D2adsorbed on graphene and graphite

Phase diagram of D2adsorbed on graphene and graphite

Monolayers of ortho-H2, para-H2, para-D2 and normal-H2 adsorbed on NaCl(001) single crystal surfaces

Phonons and specific heat of neon and methane on the surface of a nanotube bundle

Contact Info

Product

Resources

About