Isotope effects in lithium hydride and lithium deuteride crystals by molecular dynamics simulations - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Physics: Condensed Matter Année : 2012

Isotope effects in lithium hydride and lithium deuteride crystals by molecular dynamics simulations

Résumé

Molecular dynamics (MD) simulations have been carried out to study isotope effects in lithium hydride and lithium deuteride crystals. Quantum effects on nuclear motion have been included through a quantum thermal bath (QTB). The interatomic forces were described either within the density-functional theory (DFT) in the generalized gradient approximation (GGA) or by the phenomenological approach using the shell model. For both models, the isotopic shift in the lattice parameter can be successfully predicted by QTB-MD simulations. The slope of the experimental isotopic shift in pressure is satisfactorily reproduced by QTB-MD within DFT-GGA, in contrast to both density-functional perturbation theory and QTB-MD with the shell model. We have analyzed the reasons of these discrepancies through the vibrational densities of states and the isotopic shifts in bulk modulus. The results illustrate the importance of anharmonic contributions to vibrations and to the isotopic pressure shift between LiH and LiD.
Fichier principal
Vignette du fichier
LiH-JPCM_Dammak_a.pdf (168.57 Ko) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-01932743 , version 1 (23-11-2018)

Identifiants

Citer

Hichem Dammak, Ekaterina Antoshchenkova, Marc Hayoun, Fabio R.D. Finocchi. Isotope effects in lithium hydride and lithium deuteride crystals by molecular dynamics simulations. Journal of Physics: Condensed Matter, 2012, 24, pp.435402. ⟨10.1088/0953-8984/24/43/435402⟩. ⟨hal-01932743⟩
291 Consultations
432 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More