Mechanism for singular behavior in vibrational spectra of topologically disordered systems: Short-range attractions

Ten-Ming Wu*, S. L. Chang, K. H. Tsai

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

At low-enough fluid densities, we have found some naive singular behavior, like the van Hove singularities in the phonon spectra of lattices, appearing in the instantaneous normal mode spectra of the Lennard-Jones (LJ) 2n-n fluids, which serve as a prototype of topologically disordered systems. The singular behavior cannot be predicted by the mean-field theory, but interpreted by the perturbed binary modes of some special pairs, called the mutual nearest neighbor pairs, at separations corresponding to the extreme binary frequencies, which are solely determined by the attractive part of the LJ 2n-n pair potential. By reducing the range of attraction in the pair potential under the conditions of the same particle diameter and well depth, the tendency for the appearance of the singular behavior shifts to higher fluid densities. From this study, we conclude that pair potential with a short-range attraction can be a mechanism to produce a counterpart of the van Hove singularity in the vibrational spectra of disordered systems without a reference lattice.

Original languageEnglish
Article number204501
JournalJournal of Chemical Physics
Volume122
Issue number20
DOIs
StatePublished - 22 May 2005

Fingerprint Dive into the research topics of 'Mechanism for singular behavior in vibrational spectra of topologically disordered systems: Short-range attractions'. Together they form a unique fingerprint.

Cite this