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Molecular dynamics simulation of high frequency (1010 to 10 12 Hz) dielectric absorption in the Hollandite Nax(Ti 8-xCrx)O16

Khoo, K. L., Dissado, L. A., Fothergill, J. & Youngs, I. J. (2004). Molecular dynamics simulation of high frequency (1010 to 10 12 Hz) dielectric absorption in the Hollandite Nax(Ti 8-xCrx)O16. Proceedings of the 2004 IEEE International Conference on Solid Dielectrics ICSD 2004, 2, pp. 550-553. doi: 10.1109/icsd.2004.1350490


The charge-compensating sodium ions that reside interstitially in the one-dimensional tunnels of the hollandite Nax(Ti8-xCrx)O16 are used as a simple model for a fluid. Molecular dynamics are used to calculate the motions of the ions at a range of temperatures between 200 K and 373 K. The polarization response of the system to a step-up electric field is calculated for field strengths between 7.43 MV/m and 74.3 GV/m, and converted to an ac susceptibility. A resonance absorption is found,peaking at frequencies between 4.5x1010 and 8.8x1010 Hz at 297K. The origin of the response is shown to be the anharmonically coupled ion vibrations damped by ion hopping to neighbouring sites. The relationship of the result to the experimentally observed Poley absorption is explored, and a brief comparison of the calculated dynamics to previous theoretical models is made.

Publication Type: Article
Additional Information: © 2004 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
Subjects: T Technology > TA Engineering (General). Civil engineering (General)
Departments: Presidents's Portfolio
School of Science & Technology > Engineering
SWORD Depositor:
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