title: Anharmonic thermal oscillations of the electron momentum distribution in lithium fluoride.
abstract: Anharmonic thermal effects on the electron momentum distribution of a lithium fluoride single crystal are experimentally measured through high-resolution Compton scattering and theoretically modeled with ab initio simulations, beyond the harmonic approximation to the lattice potential, explicitly accounting for thermal expansion. Directional Compton profiles are measured at two different temperatures, 10 and 300 K, with a high momentum space resolution (0.10 a.u. in full width at half maximum), using synchrotron radiation. The effect of temperature on measured directional Compton profiles is clearly revealed by oscillations extending almost up to |p|=4  a.u., which perfectly match those predicted from quantum-mechanical simulations. The wave-function-based Hartree-Fock method and three classes of the Kohn-Sham density functional theory (local-density, generalized-gradient, and hybrid approximations) are adopted. The lattice thermal expansion, as described with the quasiharmonic approach, is found to entirely account for the effect of temperature on the electron momentum density within the experimental accuracy.
authors.affiliation: Dipartimento di Chimica and Centre of Excellence NIS (Nanostructured Interfaces and Surfaces), Università di Torino, via Giuria 5, IT-10125 Torino, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Erba
authors.affiliation: Dipartimento di Chimica and Centre of Excellence NIS (Nanostructured Interfaces and Surfaces), Università di Torino, via Giuria 5, IT-10125 Torino, Italy.|Laboratório de Combustíveis e Materiais, INCTMN-UFPB, Universidade Federal da Paraíba, CEP 58051-900, João Pessoa, Paraíba, Brazil.
authors.forename: J
authors.initials: J
authors.lastname: Maul
authors.affiliation: Japan Synchrotron Radiation Research Institute, SPring-8 1-1-1 Kouto, Sayo, Hyogo 679-5198 Japan.
authors.forename: M
authors.initials: M
authors.lastname: Itou
authors.affiliation: Dipartimento di Chimica and Centre of Excellence NIS (Nanostructured Interfaces and Surfaces), Università di Torino, via Giuria 5, IT-10125 Torino, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Dovesi
authors.affiliation: Japan Synchrotron Radiation Research Institute, SPring-8 1-1-1 Kouto, Sayo, Hyogo 679-5198 Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Sakurai