TiO₂-II is a high pressure form of titania with a density about 2% larger than that of rutile. In contrast to the common polymorphs anatase, brookite and rutile its electronic structure and optical properties are poorly characterized. Here we report on a comparative electron-energy-loss-spectroscopy (EELS) study for which high resolution valence-loss and core-loss EELS data were acquired from nanocrystalline (<75 ​nm sized) titania particles with an energy resolution of about 0.2 ​eV. Electronic structure features revealed from titanium L_3,2 and oxygen K electron energy loss near-edge structures show a strong similarity of TiO₂-II with both rutile and brookite, which is attributed to similarities in the connectivity of octahedral TiO₆ units with neighboring ones. From combined valence-loss EELS and UV-VIS diffuse reflectance spectroscopy data the band gap of TiO₂-II was determined to be indirect and with a magnitude of ∼3.18 ​eV, which is very similar to anatase (indirect, ∼3.2 ​eV), and distinctly different from rutile (direct, ∼3.05 ​eV) and brookite (direct, ∼3.45 ​eV).

TiO ₂ -II 是一种高压形式的二氧化钛，密度比金红石大约2%。与常见的多晶型锐钛矿、板钛矿和金红石相比，其电子结构和光学特性的表征较差。在这里，我们报告了一项比较电子能量损失能谱 (EELS) 研究，该研究从能量分辨率约为 0.2 的纳米晶体（<75 纳米尺寸）二氧化钛颗粒中获取了高分辨率的价损失和核心损失 EELS 数据eV。钛L _3,2和氧K电子能量损失近边结构揭示的电子结构特征与 TiO _{2具有很强的相似性}-II 同时具有金红石和板钛矿，这归因于八面体 TiO ₆单元与相邻单元的连通性的相似性。_{根据结合的价损失 EELS 和 UV-VIS 漫反射光谱数据，确定 TiO 2} -II的带隙是间接的，幅度为 ~3.18 eV，这与锐钛矿非常相似（间接，~3.2 eV ），并且明显不同于金红石（直接，~3.05 eV）和板钛矿（直接，~3.45 eV）。