Title

Vibrations of Au-13 and FeAu12 nanoparticles and the limits of the Debye temperature concept

Authors

Authors

G. Shafai; M. A. Ortigoza;T. S. Rahman

Comments

Authors: contact us about adding a copy of your work at STARS@ucf.edu

Abbreviated Journal Title

J. Phys.-Condes. Matter

Keywords

TOTAL-ENERGY CALCULATIONS; GOLD CLUSTERS; MOLECULAR-DYNAMICS; DEPENDENCE; CHEMISTRY; CATALYSIS; COPPER; SIZE; Physics, Condensed Matter

Abstract

We present first-principles calculations of the vibrational density of states (VDOS), the specific heat and the mean-squared displacement of the five lowest-energy isomers of Au-13 and of two low-energy FeAu12 nanoparticles. We find that the vibrational contributions to the Helmholtz energy do not affect the energy ordering of the isomers. As expected, for nanoparticles the vibrational density of states differs dramatically from the function proposed by the Debye model. We demonstrate that, for the nanoclusters we studied, the alternative calculations of the 'Debye temperature' yield significantly inconsistent results. We conclude that T-D obtained from a particular thermodynamic property is neither applicable for deriving conclusions about other thermodynamic properties nor correlated with atomic bond strengths. Instead, in order to describe the temperature dependence of a nanoparticle's mean-squared displacement and its specific-heat capacity, what is necessary is its discrete phonon spectrum.

Journal Title

Journal of Physics-Condensed Matter

Volume

24

Issue/Number

10

Publication Date

1-1-2012

Document Type

Article

Language

English

First Page

8

WOS Identifier

WOS:000301176300029

ISSN

0953-8984

Share

COinS