Structure, Energetics, and Dynamics of Screw Dislocations in Even n-Alkane Crystals
MetadataShow full item record
This research was supported under Australian Research Council grants FT130100463 and DP140101776
Spiral hillocks on n-alkane crystal surfaces were observed immediately after Frank recognized the importance of screw dislocations for crystal growth, yet their structures and energies in molecular crystals remain ill-defined. To illustrate the structural chemistry of screw dislocations that are responsible for plasticity in organic crystals and upon which the organic electronics and pharmaceutical industries depend, molecular dynamics was used to examine heterochiral dislocation pairs with Burgers vectors along  in n-hexane, n-octane, and n-decane crystals. The cores were anisotropic and elongated in the (110) slip plane, with significant local changes in molecular position, orientation, conformation, and energy. This detailed atomic level picture produced a distribution of strain consistent with linear elastic theory, giving confidence in the simulations. Dislocations with doubled Burgers vectors split into pairs with elementary displacements. These results suggest a pathway to understanding the mechanical properties and failure associated with elastic and plastic deformation in soft crystals.
Showing items related by title, author, creator and subject.
Rossiter, Angelina Jane (2009)Due to the ductile nature of the sodium nitrate crystal which deforms plastically under high levels of strain, most of the crystal growth studies in aqueous solution have focussed on the influence of tensile strain, ...
Defects and dislocations in MgO: atomic scale models of impurity segregation and fast pipe diffusionZhang, Feiwu; Walker, A.; Wright, K.; Gale, Julian (2010)Dislocations are known to influence the formation and migration of point defects in crystalline materials. We use a recently developed method for the simulation of the cores of dislocations in ionic materials to study the ...
Large scale atomistic simulation with electrostatics: The case of cation impurity segregation along an edge dislocation lineZhang, F.; Wright, Kathleen; Gale, Julian; Walker, A. (2010)The movement of impurities and point defects in materials plays a key role in determining their rheological properties, both by permitting diffusional creep and by allowing recovery by dislocation climb. Impurity and point ...