Using density functional theory (DFT) the first-principles calculations are employed to systematically investigate the effect of hydrostatic compression on the structural, elastic, electronic, thermal and thermodynamic properties of ternary silicides Li₂TmSi₃ (Tm = Ir, Pt, Rh, Os) with the ground-state optical features. The gradual decrease of bond length, unit cell volume and a smooth change of c/a with pressure deny the possibility of pressure induced phase transition up to 50 GPa. All the compounds studied here are mechanically stable within the considered pressure range. The constants C₁₁, C₁₂, C₁₃ and C₃₃ exhibit an almost linear increase trend with increase of pressure, while C₄₄ shows anomalous behavior. The bond-stretching and bond-bending force constants are calculated based on the data of elastic constants and their pressure dependent behavior are discussed. Hydrostatic pressure enhances the inherent elastic anisotropy of Li₂TmSi₃. The ternary silicides studied here cannot be easily compressed under uniaxial stress. The atomic bonds between the nearest neighbors along [001] direction are stronger than those along [100] direction in the whole range of pressure. All ternary silicides except Li₂PtSi₃ are brittle in nature at ambient pressure. Under elevated pressure all studied compounds show brittle to ductile transition except Li₂PtSi₃ that exhibits brittle nature under 10 GPa. The shear modulus of Li₂OsSi₃ shows anomalous change under pressure, which may be attributed from its anomalous change of θ_D. The higher melting point of all silicides implies that they might have possible uses in harsh environments. The TDOS at E_F in Li₂TmSi₃ decreases almost linearly with pressure. Pressure and temperature dependent thermodynamic properties and ground-state optical functions are described with implications, which may be supportive for further investigation of these compounds through experiments and theories.

使用密度泛函理论（DFT）进行第一性原理计算，系统地研究了静水压缩对三元硅化物Li ₂ TmSi ₃（Tm = Ir，Pt，Rh， Os）具有基态光学功能。键长，单位晶胞体积的逐渐减小以及c / a随压力的平滑变化都否认了压力引起的相变高达50 GPa的可能性。此处研究的所有化合物在所考虑的压力范围内均具有机械稳定性。常数C ₁₁，C ₁₂，C ₁₃和C ₃₃随压力的增加呈现出几乎线性的增长趋势，而C ₄₄表现出异常的行为。基于弹性常数的数据计算出粘结拉伸力常数和粘结弯曲力常数，并讨论了它们的压力依赖性行为。静水压力提高了Li ₂ TmSi ₃的固有弹性各向异性。本文研究的三元硅化物在单轴应力下不易压缩。在整个压力范围内，沿[001]方向的最近邻居之间的原子键要比沿[100]方向的原子键更强。除Li ₂ PtSi ₃以外的所有三元硅化物在环境压力下本质上是脆性的。在升高的压力下，所有研究的化合物均显示出脆性至延性的转变，但Li ₂ PtSi ₃在10 GPa下表现出脆性。李的剪切模量₂ OSSI _3个压力下显示异常变化，其可以从它的异常变化可归因θ _d。所有硅化物的熔点较高，意味着它们可能在恶劣的环境中使用。Li ₂ TmSi ₃中E _F处的TDOS随压力几乎呈线性下降。描述了与压力和温度有关的热力学性质和基态光学功能，这可能有助于通过实验和理论进一步研究这些化合物。