Bandura A V, Evarestov R A, Lukyanov S I
Department of Quantum Chemistry, St Petersburg State University, 26 Universitetsky Avenue, Peterhof, St Petersburg 198504, Russia.
Phys Chem Chem Phys. 2014 Jul 28;16(28):14781-91. doi: 10.1039/c4cp00903g.
A new method of theoretical modelling of polyhedral single-walled nanotubes based on the consolidation of walls in the rolled-up multi-walled nanotubes is proposed. Molecular mechanics and ab initio quantum mechanics methods are applied to investigate the merging of walls in nanotubes constructed from the different phases of titania. The combination of two methods allows us to simulate the structures which are difficult to find only by ab initio calculations. For nanotube folding we have used (1) the 3-plane fluorite TiO2 layer; (2) the anatase (101) 6-plane layer; (3) the rutile (110) 6-plane layer; and (4) the 6-plane layer with lepidocrocite morphology. The symmetry of the resulting single-walled nanotubes is significantly lower than the symmetry of initial coaxial cylindrical double- or triple-walled nanotubes. These merged nanotubes acquire higher stability in comparison with the initial multi-walled nanotubes. The wall thickness of the merged nanotubes exceeds 1 nm and approaches the corresponding parameter of the experimental patterns. The present investigation demonstrates that the merged nanotubes can integrate the two different crystalline phases in one and the same wall structure.
提出了一种基于卷曲多壁纳米管中管壁合并的多面体单壁纳米管理论建模新方法。应用分子力学和从头算量子力学方法研究由不同相二氧化钛构建的纳米管中管壁的合并。两种方法的结合使我们能够模拟仅通过从头算计算难以找到的结构。对于纳米管折叠，我们使用了：（1）三平面萤石TiO₂层；（2）锐钛矿（101）六平面层；（3）金红石（110）六平面层；以及（4）具有纤铁矿形态的六平面层。所得单壁纳米管的对称性明显低于初始同轴圆柱形双壁或三壁纳米管的对称性。与初始多壁纳米管相比，这些合并的纳米管具有更高的稳定性。合并纳米管的壁厚超过1nm，接近实验图案的相应参数。本研究表明，合并后的纳米管可以在同一壁结构中整合两种不同的晶相。
