使用基于密度泛函理论的第一性原理赝势平面波方法，对Ca3Si4块体进行了详细的计算研究，得到了金属间化合物Ca3Si4是一种间接带隙半导体，禁带宽度为0.372 eV；价带主要由Si的3s和3p态电子构成，导带主要由Ca的3d态电子构成。其光学性质结果为：静态介电常数为19，折射率为4.35，吸收系数最大峰值为1.56×105 cm-1，能量损失峰的最大值约在8.549 eV处。

The bulk of Ca3Si4 is investigated by using first principles pseudo-potential calculations based on the density function theory. The results show that Ca3Si4 is a semiconducting material with an indirect band gap and the band gap is 0.372 eV. The valence bands of Ca3Si4 are mainly composed of Si 3p as well as 3s, the conduction bands are mainly composed of Ca 3d. The optical properties of Ca3Si4 are that the static dielectric constant is 19, the refractive index is 4.35, the absorption coefficient maximum is 1.56×105 cm-1, and the value of the loss function becomes maximum at 8.549 eV.