Eshelby untwisting. Issue 45 (7th May 2021)

• Record Type: Journal Article
• Authors: Zhong, Xiaodi; Zhou, Hengyu; Li, Chao; Shtukenberg, Alexander G.; Ward, Michael D.; Kahr, Bart
• Is Part Of: Chemical communications. Volume 57:Issue 45(2021)
• Page Start: 5538
• Page End: 5541
• Publication Date: 2021-05-07
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1039/d1cc01431e
• Languages: English
• ISSNs: 1359-7345

Abstract

Abstract : The concept of Eshelby untwisting, the effect of an axial screw dislocation driving an intrinsically twisted nanocrystal towards a straighter configuration more consistent with long–range translational symmetry, is introduced here. Abstract : The concept of Eshelby untwisting, the effect of an axial screw dislocation driving an intrinsically twisted nanocrystal towards a straighter configuration more consistent with long–range translational symmetry, is introduced here. Force-field simulations of nanorods built from the enantiomorphous (space groups, P 31 21 and P 32 21) crystal structures of benzil (C6 H5 –C(O)–C(O)–C6 H5 ) were previously shown to twist in opposite directions, even in the absence of dislocations. Here, both right- and left-handed screw dislocations were introduced into benzil nanorods in silico . For rods built from the P 32 21 enantiomorph, dislocations with negative Burgers vectors increased the right-handed twisting already present in the intrinsically twisted structures without dislocations, whereas dislocations with positive Burgers vectors drove the twisted structure back towards a straight configuration, untwisting. In the dynamic simulations, the P 32 21 helicoid endowed with a positive Burgers vector ultimately twisted back through the straight configuration, until a helicoid of opposite sense from that of the starting structure, was obtained. The bearing of these observations on the propensity of small crystals to adopt non-polyhedral morphologies is discussed.