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Professor Peter R Harrowell

Professor of Chemistry and Director of Postgraduate Studies

Contact Details

School of Chemistry, Building F11
The University of Sydney, NSW, 2006
Australia
Email address: peter.harrowell@sydney.edu.au
Telephone: +61 (2)9351-4102
Fax: +61 (2) 9351-3329

Career Profile

  • B.Sc. (University of Sydney)
  • Ph.D. (University of Chicago)

Areas of interest

  • statistical mechanics
  • nucleation
  • crystal growth
  • rheology of ordered materials
  • transitions in nonequilibrium systems
  • computer simulation methods
  • liquid crystals
  • glass transitions
  • theory of highly cooperative dynamics
  • the physics of biological processes
  • history of science

Research

Glass Transition: We are carrying out detailed analysis of the nature of slow relaxation in some simple models of glass forming liquids using computer simulations and theoretical treatments.
In studies of a facilitated kinetic Ising model [Harrowell, Phys.Rev.E, 48, 4359 (1993)] we concluded that the glassy dynamics was the result of an increasing inhomogeneity in the spatial distribution of relaxation kinetics.

This insight has proved a valuable approach to the analysis of structural relaxation in simple liquids [Hurley and Harrowell, Phys.Rev.E, 52, 1694 (1995), J.Chem.Phys., to be published (1996)]. It also provides a valuable general framework with which to relate the range of glass behaviour [Perera and Harrowell, Phys.Rev.E, 54, 1652 (1996)]. We are currently undertaking a detailed study of nature of relaxation and structural fluctuations in supercooled biinary liquid mixtures in 2D using molecular dynamic simulations and theoretical descriptions of the collective processes.

Shear Induced Transitions in Colloidal Suspensions: Extensive nonequilibrium simulations of dilute suspensions of charged colloidal particles have been undertaken with the aim of establishing the correct physical picture of the order/disorder transitions observed experimentally under the influence of shear. We have reproduced the shear induced disordering transition observed in colloidal crystals [Butler and Harrowell, J.Chem.Phys. 103, 4653 (1995)] and established that long wavelength fluctuations play a central role in the transition, unlike its equilibrium analogue. We have also demonstrated that the frequently reported observation of shear induced ordering in simulated liquids CAN arise as an artefact of shearing a liquid through periodic boundary conditions [Butler and Harrowell, J.Chem.Phys. 105, 605 (1996)]. The kinetics of crystallization in a shearing suspension has also been examined [Butler and Harrowell, Phys.Rev.E, 52, 6424 (1996)].

Current work focuses on developing a clearer insight into the coupling of shear flow with structural fluctuations.

The Stabilization of Layered Liquid Crystal Phases: We have just completed a Monte Carlo simulation study of the role of flexible end chains on stabilizing Smectic A and Smectic C phases of liquid crystals. We have demonstrated for the first time that both phases can be stabilized from purely entropic effects [Casey and Harrowell, in preparation]. Ongoing work involves the study of phase transitions in small clusters of mesogens.

Crystal Growth: Our current work involves looking at two questions. The first is the description of crystallization involving density change under conditions of constant N and V (as is often the case). Under these conditions the supercooling is, itself, varying with time [Wild and Harrowell, in preparation]. The second problem considers the relationship between a crystal surface's ability to organize the adjacent liquid and the kinetics of the growth process. Our current work builds on earlier results [Williams, Moss and Harrowell, J.Chem.Phys. 99, 3998 (1993); Moss and Harrowell, J.Chem.Phys. 100, 7630 (1994)] in which we showed that close packed surfaces with short range interactions were unable to fully break the symmetry of the adjacent liquid and hence the growth of these surfaces was impeded.

Publications (2009 to 2012)

  1. Ronceray, P and Harrowell, P. Geometry and the entropic cost of locally favoured structures in a liquid. The Journal of Chemical Physics, 136 (13), 134504, 2012. DOI: 10.1063/1.3701617

  2. de Souza, VK and Harrowell, P. Structurally determined directionality identifies the boundary between mobile and immobile domains in a disordered material. The Journal of Chemical Physics, 136 (5), 054507, 2012. DOI: 10.1063/1.3681364

  3. de Souza, VK and Harrowell, P. The influence of overconstraint on the spatial distribution of mobility in an amorphous network. The Journal of Chemical Physics, 135 (19), 194505 (5pp), 2011. DOI: 10.1063/1.3662073

  4. Pedersen, UR and Harrowell, P.  Factors contributing to the glass-forming ability of a simulated molecular liquid. The Journal of Physical Chemistry B, 115 (48), 14205-14209, 2011. DOI: 10.1021/jp205013w


  5. Widmer-Cooper, A and Harrowell, P. Structural phases in non-additive soft-disk mixtures: Glasses, substitutional order, and random tilings. The Journal of Chemical Physics, 135, 224515, 2011. DOI: 10.1063/1.3666010

  6. Ronceray, P and Harrowell, P. The variety of ordering transitions in liquids characterized by a locally favoured structure. EPL, A Letters Journal Exploring the Frontiers of Physics, 96 (3), 36005, 2011. DOI: 10.1209/0295-5075/96/36005

  7. Wen, P, Harrowell, Pand Angell, CA. Fast and slow components in the crystallization of a model multicomponent system, NaKCa(NO3): The role of composition fluctuations. The Journal of Physical Chemistry A, 115 (23), 6260-6268, 2011. DOI: 10.1021/jp111835z

  8. Huang, DM and Harrowell, P. Controlling adsorbate diffusion on a high-symmetry surface through molecular shape selection. The Journal of Physical Chemistry C, 115 (19), 9526-9534, 2011. DOI: 10.1021/jp1108619

  9. Hudson, TS and Harrowell, P. Structural searches using isopointal sets as generators: Densest packings for binary hard sphere mixtures. Journal of Physics: Condensed Matter, 23 (19), 194103 (6pp), 2011. DOI: 10.1088/0953-8984/23/19/194103

  10. Wen, P; Paraska, D; Baker, R and Harrowell, P. Molecular engineering of the glass transition: Glass-forming ability across a homologous series of cyclic stilbenes. The Journal of Physical Chemistry B, 115 (16), 4696-4702, 2011. DOI: 10.1021/jp110975y

  11. Pedersen, UR; Hudson, TS and Harrowell, P. Crystallization of the Lewis-Wahnström ortho-terphenyl model. The Journal of Chemical Physics, 134 (11), 114501 (6pp), 2011. DOI: 10.1063/1.3559153

  12. Harrowell, P; Fernández, JR and Miracle, DB. The chemically ordered glass: The limiting composition for chemical order in amorphous packings of hard-sphere mixtures. Molecular simulation, 37 (4), 293-298, 2011. DOI: 10.1080/08927022.2010.548386

  13. de Souza, VK and Harrowell, P. Length scales of dynamic heterogeneities in a network of fluctuating mechanical constraints. Physical Review E, 83 (1), 011501 (5pp), 2011. DOI: 10.1103/PhysRevE.83.011501

  14. Leonard, S and Harrowell, P. Macroscopic facilitation of glassy relaxation kinetics: Ultrastable glass films with frontlike thermal response. The Journal of Chemical Physics, 133 (24), 244502 (12pp), 2010. DOI: 10.1063/1.3511721

  15. Candelier, R; Widmer-Cooper, A; Kummerfeld, JK; Dauchot, O; Biroli, G; Harrowell, P and Reichman, DR. Spatiotemporal hierarchy of relaxation events, dynamical heterogeneities, and structural reorganization in a supercooled liquid. Physical Review Letters, 105 (13), 135702 (pp 1-4), 2010. DOI: 10.1103/PhysRevLett.105.135702

  16. Harrowell, P. On the existence of a structural instability in sub-critical crystalline fluctuations in a supercooled liquid. Journal of Physics: Condensed Matter, 22 (36), 364106 (pp 1-5), 2010. DOI: 10.1088/0953-8984/22/36/364106

  17. Pedersen, UR; Schrøder, TB; Dyre, JC and Harrowell, P. Geometry of slow structural fluctuations in a supercooled binary alloy. Physical Review Letters, 104 (10), 105701 (4pp), 2010. DOI: 10.1103/PhysRevLett.104.105701

  18. Widmer-Cooper, A and Harrowell, P. Central role of thermal collective strain in the relaxation of structure in a supercooled liquid. Physical Review E, 80 (6), 061501 (6 pages), 2009. DOI: 10.1103/PhysRevE.80.061501

  19. Widmer-Cooper, A; Perry, H; Harrowell, P and Reichman, DR. Localized soft modes and the supercooled liquid’s irreversible passage through its configuration space. The Journal of Chemical Physics, 131 (19), 194508 (12 pages), 2009. DOI: 10.1063/1.3265983

  20. de Souza, VK and Harrowell, P. Unconstrained motions, dynamics heterogeneities, and relaxation in disordered solids. Physical Review E, 80 (4), 041503(1-11), 2009. DOI: 10.1103/PhysRevE.80.041503

  21. de Souza, VK and Harrowell, P. Rigidity percolation and the spatial heterogeneity of soft modes in disordered materials. Proceedings of the National Academy of Sciences, 106 (36), 15136-15141, 2009. DOI: 10.1073/pnas.0901112106

  22. Ping, W; Harrowell, P; Byrne, N and Angell, CA. Composition dependence of the solid state transitions in NaNO3/KNO3 mixtures. Thermochimica Acta, 486 (1-2), 2009. DOI: 10.1016/j.tca.2008.12.017

  23. Miracle, DB and Harrowell, P. Noncrystalline compact packings of hard spheres of two sizes: Bipyramids and the geometry of common neighbors. Journal of Chemical Physics, 130 (11), 114505, 2009. DOI: 10.1063/1.3082008

  24. Petravic, J and Harrowell, P. Spatial dependence of viscosity and thermal conductivity through a planar interface. Journal of Physical Chemistry B, 113 (7), 2059-2065, 2009. DOI: 10.1021/jp807254b