Abstract Nanostructures of the naturally-existing most stable iron oxide, hematite (α-Fe2O3), gain significant research interest in various recent applications. In this study, we put the main focus on magneto-optical (MO) properties of hematite nanoparticles synthesized by a solvothermal approach, and the effects of size, morphology, and particle aggregation on the magnetic circular dichroism (MCD) and conventional absorption spectra are investigated. Simultaneous deconvolution of UV–vis absorption and MCD spectra allows us to discuss the nature of electronic transitions of various hematite nanoarchitectures on the basis of possible transitions in the 3d5 system, giving enhanced spectral resolution and detailed assignments. Consequently, we find (i) characteristic size- and shape-dependent MCD responses at 450–470 nm; and (ii) the presence of both spin-allowed pair excitation and Laporte-forbidden d–d transition with opposite MCD signs in close energy at around 550 nm.

中文翻译：

---

不同尺寸和形态的 α-Fe2O3 赤铁矿纳米粒子的电子跃迁：通过紫外-可见吸收和 MCD 光谱的同时解卷积分析

摘要 天然存在的最稳定的氧化铁赤铁矿 (α-Fe2O3) 的纳米结构在最近的各种应用中获得了显着的研究兴趣。在这项研究中，我们主要关注通过溶剂热法合成的赤铁矿纳米粒子的磁光 (MO) 特性，尺寸、形态和粒子聚集对磁性圆二色性 (MCD) 和常规吸收光谱的影响是调查。UV-vis 吸收和 MCD 光谱的同时解卷积使我们能够根据 3d5 系统中可能的跃迁讨论各种赤铁矿纳米结构的电子跃迁的性质，从而提高光谱分辨率和详细分配。因此，我们发现 (i) 450-470 nm 处的特征尺寸和形状相关 MCD 响应；