- Physical Review Journals
All JournalsPhysics Magazine
Access Provided by Xinjiang University

Physical Review E

Export citation

Export citation

Choose format for download:

Download Citation
  • Access by Xinjiang University

Rotational dynamics of simple asymmetric molecules

D. Fragiadakis and C. M. Roland

  • Naval Research Laboratory, Chemistry Division, Code 6120, Washington DC 20375-5342, USA

PDF

Phys. Rev. E 91, 022310 – Published 24 February, 2015

DOI: https://doi.org/10.1103/PhysRevE.91.022310

Abstract

Molecular dynamic simulations were carried out on rigid diatomic molecules, which exhibit both α (structural) and β (secondary) dynamics. The relaxation scenarios range from onset behavior, in which a distinct α process emerges on cooling, to merging behavior, associated with two relaxation peaks that converge at higher temperature. These properties, as well as the manifestation of the β peak as an excess wing, depend not only on thermodynamic conditions, but also on both the symmetry of the molecule and the correlation function (odd or even) used to analyze its dynamics. These observations help to reconcile divergent results obtained from different experiments. For example, the β process is more intense and the α-relaxation peak is narrower in dielectric relaxation spectra than in dynamic light scattering or NMR measurements. In the simulations herein, this follows from the weaker contribution of the secondary relaxation to even-order correlation functions, related to the magnitude of the relevant angular jumps.

View figure in article

Article Text

References (40)

  1. C. A. Angell, J. Phys. Chem. Solids 49, 863 (1988).
  2. A. Kudlik, S. Benkhof, T. Blochowicz, C. Tschirwitz, and E. Rössler, J. Mol. Struct. 479, 201 (1999).
  3. E. Donth, The Glass Transition: Relaxation Dynamics in Liquids and Disordered Materials (Springer, New York, 2001).
  4. N. P. Bailey, T. Christensen, B. Jakobsen, K. Niss, N. B. Olsen, U. R. Pedersen, T. B. Schroder, and J. C. Dyre, J. Cond. Phys. Cond Mat. 20, 244113 (2008).
  5. C. M. Roland, Viscoelastic Behavior of Rubbery Materials (Oxford University Press, Oxford, 2011).
  6. S. Capaccioli, M. Paluch, D. Prevosto, L. M. Wang, and K. L. Ngai, J. Phys. Chem. Lett. 3, 735-743 (2012).
  7. K. L. Ngai, S. Mashimo, and G. Fytas, Macromolecules 21, 3030 (1988).
  8. C. H. Wang, G. Fytas, D. Lilge, and Th. Dorfmüller, Macromolecules 14, 1363 (1981).
  9. G. Fytas, A. Patkowski, G. Meier, and Th. Dorfmüller, J. Chem. Phys. 80, 2214 (1984).
  10. G. Fytas, C. H. Wang, G. Meier, and E. W. Fischer, Macromolecules 18, 1492 (1985).
  11. A. Brodin, R. Bergman, J. Mattson, and E. A. Rössler, Eur. Phys. J. B 36, 349 (2003).
  12. N. Petzold, B. Schmidtke, R. Kahlau, D. Bock, R. Meier, B. Micko, D. Kruk, and E. A. Rössler, J. Chem. Phys. 138, 12A510 (2013).
  13. L. Comez, D. Fioretto, L. Palmieri, L. Verdini, P. A. Rolla, J. Gapinski, T. Pakula, A. Patkowski, W. Steffen, and E. W. Fischer, Phys. Rev. E 60, 3086 (1999).
  14. C. Gainaru, O. Lips, A. Troshagina, R. Kahlau, A. Brodin, F. Fujara, and E. A. Rössler, J. Chem. Phys. 128, 174505 (2008).
  15. D. Fragiadakis and C. M. Roland, Phys. Rev. E 86, 020501(R) (2012).
  16. D. Fragiadakis and C. M. Roland, Phys. Rev. E 88, 042307 (2013).
  17. D. Fragiadakis and C. M. Roland, Phys. Rev. E 89, 052304 (2014).
  18. K. L. Ngai and M. Paluch, J. Chem. Phys. 120, 857 (2004).
  19. A. J. Moreno, S.-H. Chong, W. Kob, and F. Sciortino, J. Chem. Phys. 123, 204505 (2005).
  20. S.-H. Chong, A. J. Moreno, F. Sciortino, and W. Kob, Phys. Rev. Lett. 94, 215701 (2005).
  21. S. Kämmerer, W. Kob, and R. Schilling, Phys. Rev. E 56, 5450 (1997).
  22. C. De Michele and D. Leporini, Phys. Rev. E 63, 036702 (2001).
  23. M. Higuchi and T. Odagaki, J. Phys. Soc. Jpn. 71, 735 (2002).
  24. M. Higuchi, J. Matsui, and T. Odagaki, J. Phys. Soc. Jpn. 72, 178 (2003).
  25. D. Bedrov and G. D. Smith, Phys. Rev. E 71, 050801(R) (2005).
  26. D. Bedrov and G. D. Smith, J. Non-Cryst. Solids 357, 258 (2011).
  27. HOOMD web page: http://codeblue.umich.edu/hoomd-blue.
  28. J. A. Anderson, C. D. Lorenz, and A. Travesset, J. Comput. Phys. 227, 5342 (2008).
  29. W. Kob and H. C. Andersen, Phys. Rev. Lett. 73, 1376 (1994).
  30. C1 and C2 are calculated herein by averaging the rotational correlation functions of the individual molecules. This neglects orientational correlations between molecules, which may contribute to experimental data from, for example, dielectric spectroscopy.
  31. G. Williams, Adv. Polym. Sci. 33, 59 (1979).
  32. F. Kremer and A. Schonhals, Broadband Dielectric Spectroscopy (Springer, New York, 2003).
  33. K. Cole and R. Cole, J. Chem. Phys. 9, 341 (1941).
  34. U. Schneider, P. Lunkenheimer, R. Brand, and A. Loidl, J. Non-Cryst. Solids 235-237, 173 (1998).
  35. U. Schneider, P. Lunkenheimer, R. Brand, and A. Loidl, Phys. Rev. E 59, 6924 (1999).
  36. F. Stickel, E. W. Fischer, and R. Richert, J. Chem. Phys. 102, 6251 (1995).
  37. El. Flenner and G. Szamel, J. Chem. Phys. 138, 12A523 (2013).
  38. M. P. Eastwood, T. Chitra, J. M. Jumper, K. Palmo, A. C. Pan, and D. E. Shaw, J. Phys. Chem. B. 117, 12898 (2013).
  39. R. Casalini, K. L. Ngai, and C. M. Roland, Phys. Rev. B 68, 014201 (2003).
  40. C. León and K. L. Ngai, J. Phys. Chem. B 103, 4045 (1999).

Outline

Information

Phys. Rev. E 91, 022310– Published 24 February, 2015
  • Received 11 September 2014
  • Revised 9 January 2015
Article part of CHORUS

Published by the American Physical Society

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation