Phonons and librons in solid hydrogen and deuterium

Mertens, Franz G.; Biem, W.

doi:10.1007/bf01395050

Cited by 32 publications

(3 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The heavy Cl 2 molecule oscillates slowly enough for the hydrogen molecules to follow (almost) adiabatically and adjust their positions accordingly. This is supported by the fact that our estimates for the Cl 2 oscillation frequency, 2E 0 , are found in the low-frequency and low-density region of phonon spectra measured for the pH 2 and oD 2 crystals [55].…”

Section: A Accardi and B Schmidtsupporting

confidence: 79%

RETRACTED ARTICLE: Quantum effects on translation and rotation of molecular chlorine in solid para-hydrogen

Accardi

Schmidt

2013

Molecular Physics

View full text Add to dashboard Cite

Structure and quantum effects of a Cl 2 molecule embedded in fcc and hcp para-hydrogen (pH 2 ) crystals are investigated in the zero-temperature limit. The interaction is modelled in terms of Cl 2 -pH 2 and pH 2 -pH 2 pair potentials from ab initio CCSD(T) and MP2 calculations. Translational and rotational motions of the molecules are described within three-dimensional anharmonic Einstein and Devonshire models, respectively, where the crystals are either treated as rigid or allowed to relax. The pH 2 molecules, as well as the heavier Cl 2 molecule, show large translational zero-point energies (ZPEs) and undergo large-amplitude translational motions. This gives rise to substantial reductions in the cohesive energies and expansions of the lattices, in agreement with experimental results for pure hydrogen crystals. The rotational dynamics of the Cl 2 impurity is restricted to small-amplitude librations, again with high librational ZPEs, which are described in terms of two-dimensional non-degenerate anharmonic oscillators. The lattice relaxation causes qualitative changes of the rotational energy surfaces, which finally favour librations around the crystallographic directions pointing towards the nearest neighbours, both for fcc and hcp lattices. Implications on the reactant orientation in the experimentally observed laser-induced chemical reaction, Cl + H 2 → HCl + H, are discussed.

show abstract

Section: A Accardi and B Schmidtsupporting

confidence: 79%

RETRACTED ARTICLE: Quantum effects on translation and rotation of molecular chlorine in solid para-hydrogen

Accardi

Schmidt

2013

Molecular Physics

View full text Add to dashboard Cite

show abstract

“…The generalized density of states (GDOS) G(ω) comprises the complete phonon excitations of sD 2 as well as rotational transitions of individual D 2 molecules. Furthermore, multi-phonon excitations of the phonon system of sD 2 [14] should appear in the GDOS, as they are not corrected for in Eq. ( 2).…”

Section: Introductionmentioning

confidence: 99%

Density of states in solid deuterium: Inelastic neutron scattering study

et al. 2009

View full text Add to dashboard Cite

The dynamics of solid deuterium ͑sD 2 ͒ is studied by means of inelastic scattering ͑coherent and incoherent͒ of thermal and cold neutrons at different temperatures and para-ortho ratios. In this paper, the results for the generalized density of states ͑GDOS͒ are presented and discussed. The measurements were performed at the thermal neutron time-of-flight ͑TOF͒ instrument IN4 at ILL Grenoble and at the cold neutron TOF instrument TOFTOF at FRM II Garching. The GDOS comprises besides the hcp phonon excitations of the sD 2 the rotational transitions J ‫ۋ0=‬ 1 and J ‫ۋ1=‬ 2. The intensities of these rotational excitations depend strongly on the ortho-D 2 molecule concentration c o in sD 2 . Above E = 10 meV there are still strong excitations, which very likely may originate from higher-energy damped optical phonons and multiphonon contributions. A method for separating the one-phonon and multiphonon contributions to the density of states will be presented and discussed.

show abstract

“…15-17 We summarize here our working equations and approximations. For an anharmonic crystal X"(to) can be expressed in a general fashion in terms of the self-energy function s as X"(qff';to) lim Im{h[(to 9 Here A(to) and F(to) are the anharmonic shift and width functions, respectively.…”

Section: The Anharmonic One-phonon Spectral Functionmentioning

confidence: 99%

The phonon absorption line shape of solid molecular H2 and D2 as a function of density

Goldman

1980

J Low Temp Phys

View full text Add to dashboard Cite

A theoretical study is presented of the lattice dyhamics of the cubic phases of solid hydrogen and deuterium as a function of density. The calculations are performed in the self-consistent phonon approximation and include cubic three-phonon processes and higher anharmonic corrections. The anisotropic part of the intermolecular potential is neglected and libronic effects are not included. The line shape of the one-phonon far-infrared absorption process is studied in detail and is found to display a complex and interesting behavior as a function of pressure. The experimental absorption line is well accounted for by the one-phonon line shapes calculated here and phonon-libron and multiphonon absorption, which has been treated elsewhere. Phonon dispersion curves and elastic constants are also presented.

show abstract

Phonons and librons in solid hydrogen and deuterium

Cited by 32 publications

References 6 publications

RETRACTED ARTICLE: Quantum effects on translation and rotation of molecular chlorine in solid para-hydrogen

RETRACTED ARTICLE: Quantum effects on translation and rotation of molecular chlorine in solid para-hydrogen

Density of states in solid deuterium: Inelastic neutron scattering study

The phonon absorption line shape of solid molecular H2 and D2 as a function of density

Contact Info

Product

Resources

About