The structural, electronic and optical properties of rare-earth, scandium-based compounds within the family of RE 5 -T 2 -In 4 (T = Ni, Pd, Pt) intermetallics are calculated by using density functional theory-based orthogonalized linear combination of atomic orbitals method. The studied compounds crystallize in orthorhombic structure with space group Pbam (No. 55). The electronic properties exhibit conducting features of all three compounds. Charge transfer and crystal strength analysis were carried out by computing bond order and effective charge. Regarding optical properties the complex dielectric function, optical conductivity and electron energy loss function have been assessed. All the three compounds demonstrate optically anisotropic behaviour for energy values up to 7.0 eV and turned towards isotropic nature at higher energy (>7.0 eV). Optical conductivity spectra designate that the compounds are optically active for visible to UV light. Two major peaks are observed in energy loss spectra, at 13.2 and 32.6 eV, which correspond to plasmonic resonance points. The interatomic bonding characteristics between distinct pair of atoms within each compound have also been elaborated in comprehensive manner.

中文翻译：

---

钪基三元铟系 Sc5T2In4（T = Ni、Pd、Pt）的第一性原理结构、电子、光学和键合特性

RE 5 -T 2 -In 4 (T = Ni, Pd, Pt) 金属间化合物家族中稀土、钪基化合物的结构、电子和光学性质通过使用基于密度泛函理论的正交线性组合计算原子轨道法。所研究的化合物以正交结构结晶，空间群为 Pbam（第 55 号）。电子特性表现出所有三种化合物的导电特性。通过计算键序和有效电荷进行电荷转移和晶体强度分析。关于光学特性，已经评估了复合介电函数、光导率和电子能量损失函数。所有三种化合物在高达 7.0 eV 的能量值下都表现出光学各向异性行为，并在更高能量 (>7.0 eV) 下转向各向同性。光导率光谱表明化合物对可见光至紫外光具有光学活性。在能量损失光谱中观察到两个主要峰值，分别为 13.2 和 32.6 eV，它们对应于等离子体共振点。每种化合物中不同原子对之间的原子间键合特性也得到了全面阐述。