title: Thermal dependent anharmonicity effects on gold bulk studied by extended x-ray-absorption fine structure.
abstract: The structural parameters of the first five coordination shells of an Au bulk obtained from high accuracy L(3)-edge extended x-ray absorption fine structure (EXAFS) spectra in the temperature range 20-300 K are reported. Good agreement with previously reported studies is found. The effective second and third order force constants evaluated using EXAFS data are compatible with those calculated from phonon dispersion curves. A careful comparison of the variations of the EXAFS first shell distance with x-ray diffraction data provided the mean squared relative displacement of the atomic vibrations perpendicular to the first interatomic bond. An alternative new approach that is useful in achieving this parameter when x-ray diffraction data are not available is proposed.
authors.affiliation: Dipartimento di Fisica 'E Amaldi', Università Roma TRE, via della Vasca Navale 84, I-00146 Roma, Italy.
authors.forename: T
authors.initials: T
authors.lastname: Comaschi
authors.forename: A
authors.initials: A
authors.lastname: Balerna
authors.forename: S
authors.initials: S
authors.lastname: Mobilio