English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
 
 
DownloadE-Mail
  Energy barriers and activated dynamics in a supercooled Lennard-Jones liquid

Doliwa, B., & Heuer, A. (2003). Energy barriers and activated dynamics in a supercooled Lennard-Jones liquid. Physical Review E, 67(3): 031506.

Item is

Files

show Files

Locators

show

Creators

show
hide
 Creators:
Doliwa, B.1, Author           
Heuer, Andreas1, Author           
Affiliations:
1MPI for Polymer Research, Max Planck Society, ou_1309545              

Content

show
hide
Free keywords: -
 Abstract: We study the relation of the potential energy landscape (PEL) topography to relaxation dynamics of a small model glass former of Lennard-Jones type. The mechanism under investigation is the hopping between superstructures of PEL minima, called metabasins (MBs). Guided by the idea that the mean durations [τ] of visits to MBs should reflect the local PEL structure, we first derive the effective depths of MBs from dynamics, by the relation Eapp=d ln[τ]/dβ, where β=1/kBT. Second, we establish a connection of Eapp to the barriers that surround MBs. As the consequence of a rugged PEL, it turns out that escapes from MBs do not happen by single hops between PEL minima, but correspond to complicated multiminima sequences. We introduce the concept of return probabilities to the bottom of the MBs in order to judge when the attraction range of a MB has been left. The energy barriers overcome can then be identified. These turn out to be in good agreement with the effective depths Eapp, calculated from dynamics. We are thus able to relate MB lifetimes to their local structure. Moreover, we can trace back the overall diffusive dynamics to the population of MBs and to their local topology, i.e., to purely thermodynamic and structural quantities. Single energy barriers are identified with the help of a new method, which accurately performs a descent along the ridge between two minima. We analyze the population of transition regions between minima, called basin borders. No indication for the mechanism of diffusion to change around the mode-coupling temperature can be found. We discuss the question whether the one-dimensional reaction paths connecting two minima are relevant for the calculation of reaction rates at the temperatures under study.

Details

show
hide
Language(s): eng - English
 Dates: 2003-03
 Publication Status: Issued
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: -
 Identifiers: eDoc: 28368
ISI: 000182020700030
Other: P-03-128
 Degree: -

Event

show

Legal Case

show

Project information

show

Source 1

show
hide
Title: Physical Review E
  Alternative Title : Phys. Rev. E
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: -
Pages: - Volume / Issue: 67 (3) Sequence Number: 031506 Start / End Page: - Identifier: ISSN: 1063-651X