Lattice dynamics of noble and transition metals

A simple model for the calculation of the phonon dispersion curves of the noble and transition metals is proposed. The model uses the concept of a rigid shell moving relative to its nucleus to simulate the response of the d electrons to the nuclear motion, short range central forces for the interaction between the ion cores, and a screened pseudopotential for the conduction electron response. The most general form of the model considered for f.c.c. metals contains six parameters, three of which may be obtained from the adiabatic electric constants and the remainder from a least square fit to the experimental frequencies. Preliminary applications of the model containing five parameters made for copper and nickel have resulted in fits to the experimental dispersion curves which are within 2 and 2.5%, respectively.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49178/2/jfv5i1p17.pd

Ab-initio investigation of phonon dispersion and anomalies in palladium

In recent years, palladium has proven to be a crucial component for devices ranging from nanotube field effect transistors to advanced hydrogen storage devices. In this work, I examine the phonon dispersion of fcc Pd using first principle calculations based on density functional perturbation theory. While several groups in the past have studied the acoustic properties of palladium, this is the first study to reproduce the phonon dispersion and associated anomaly with high accuracy and no adjustable parameters. In particular, I focus on the Kohn anomaly in the [110] direction.Comment: 19 pages, preprint format, 7 figures, added new figures and discussio