采用模型化学方法,利用从头算(Ab inito)和密度泛函(DFT)方法计算研究了氧化钛Ti5O10簇模型和V4+同晶置换Ti原子的簇模型在A→R相变中的能量变化、角度崎变方式、V4+取代位置、前线轨道变化.结果表明,V2O5晶格失去1个O原子而形成的V2O4物种具有金红石型结构,可诱导或促进TiO2的A→R相变.Ti4VO10簇中的成单α电子对体系的前线轨道产生影响;价层电子分布的这种不平衡可能是导致锐钛型结构中Ti-Ti晶格发生畸变、在加热过程中更容易向金红石型结构转变的推动力.
Ab initio and DFT calculations of the Ti5 O10 cluster models of TiO2 and V4+ isomorphous replaced cluster models are carried out to study the change of total energy,the ways of angular distortion, the change of frontier orbitals and Ti4+ in the model which preferentially substituted by V4+. The calculations reflect that the V2 O4 species,which has a rutile-like structure,can promote the A→R phase transition of TiO2. The single α electron in Ti4 VO10 cluster model makes change to the frontier orbitals and the uneven contribution of electrons in valence shell may be the force driving the angular distortion in anatise lattice to rutile-like structure.
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