http://www.cnr.it/ontology/cnr/individuo/prodotto/ID193687

Proton vibrational dynamics in lithium imide investigated through incoherent inelastic and Compton neutron scattering (Articolo in rivista)

Type

Label

Proton vibrational dynamics in lithium imide investigated through incoherent inelastic and Compton neutron scattering (Articolo in rivista) (literal)

Anno

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi

Alternative label

A. Pietropaolo (1); D. Colognesi (2); M. Catti (3); A.-C. Nale (3); M. A. Adams (4); A. J. Ramirez-Cuesta (4); J. Mayers (4) (2012)
Proton vibrational dynamics in lithium imide investigated through incoherent inelastic and Compton neutron scattering
in Journal of chemical physics online; American Institute of Physics, Woodbury [NY] (Stati Uniti d'America)
(literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori

A. Pietropaolo (1); D. Colognesi (2); M. Catti (3); A.-C. Nale (3); M. A. Adams (4); A. J. Ramirez-Cuesta (4); J. Mayers (4) (literal)

Pagina inizio

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume

Rivista

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#pagineTotali

Note

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni

1) Dipartimento di Fisica \"G. Occhialini,\" Università degli Studi di Milano-Bicocca, Piazza della Scienza 3 20126 Milan, Italy; 2) Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, Sezione di Firenze, via Madonna del Piano 10, 50019 Sesto Fiorentino (FI), Italy; 3) Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, Via Cozzi 53, 20125 Milan, Italy; 4) ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, United Kingdom; (literal)

Titolo

Proton vibrational dynamics in lithium imide investigated through incoherent inelastic and Compton neutron scattering (literal)

Abstract

In the present study we report neutron spectroscopic measurements on polycrystalline lithium imide, namely, incoherent inelastic neutron scattering at 20 K, and neutron Compton scattering from 10 K up to room temperature. From the former technique the H-projected density of phonon states up to 100 meV is derived, while the latter works out the spherically averaged single-particle (i.e., H, Li, and N) momentum distributions and, from this, the mean kinetic energies. Only for H at the lowest investigated temperature, non-Gaussian components of its momentum distribution are detected. However, these components do not seem directly connected to the system anharmonicity, being fully compatible with the simple N-H bond anisotropy. Neutron data are also complemented by ab initio lattice dynamics simulations, both harmonic and, at room temperature, carried out in the framework of the so-called \"quantum colored noise thermostat\" method. The single-particle mean kinetic energies in lithium imide as a function of temperature show a quite peculiar behavior at the moment not reproduced by ab initio lattice dynamics methods, at least as far as H and Li are concerned. As matter of fact, neither their low temperature values nor their temperature trends can be precisely explained in terms of standard phonon calculations. (literal)

Editore