Vibrational dynamics and boson peak in a supercooled polydisperse liquid

Details Vibrational dynamics and boson peak in a supercooled polydisperse liquid Vibrational dynamics and boson peak in a supercooled polydisperse liquid

2009-02-22

arxiv.org/abs/0902.3807v1

Physics

Condensed Matter

Other Condensed Matter

Scientific paper

Vibrational density of states (VDOS) in a supercooled polydisperse liquid is computed by diagonalizing the Hessian matrix evaluated at the potential energy minima for systems with different values of polydispersity. An increase of polydispersity leads to an increase in relative population of the localized high-frequency modes. At low frequencies, the density of states show an excess compared to the Debye squared-frequency law, which has been identified with the boson peak. The height of the boson peak increases with polydispersity. The values of the participation ratio as well as the level spacing statistics demonstrate that the modes comprising the boson peak are largely delocalized. Interestingly, the intensity of the boson peak shows a rather narrow sensitivity to changes in temperature and is seen to persist even at high temperatures. Study of the difference spectrum at two different polydispersity reveals that the increase in the height of boson peak is due to a population shift from modes with frequencies above the maximum in the VDOS to that below the maximum, indicating an increase in the fraction of the unstable modes in the system. The latter is further supported by the facilitation of the observed dynamics by polydispersity. Since the strength of the liquid increases with polydispersity, the present result provides an evidence that the intensity of boson peak correlates positively with the strength of the liquid, as observed earlier in many experimental systems.

Affiliated with

Also associated with

No associations

Rating

Vibrational dynamics and boson peak in a supercooled polydisperse liquid does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Vibrational dynamics and boson peak in a supercooled polydisperse liquid, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Vibrational dynamics and boson peak in a supercooled polydisperse liquid will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-99389