Mehmood Shahid, Ali Zahid, Khan Shah Rukh, Ahmad Ashfaq, Khan Nasar, Mousa Mohamed
Department of Physics, University of Malakand Chakdara, Chakdara, 18800, Dir, Pakistan.
Department of Chemistry, College of Science, King Saud University, P.O. Box, 2455, Riyadh, 11451, Saudi Arabia.
J Mol Model. 2025 May 2;31(5):153. doi: 10.1007/s00894-025-06346-3.
In present study, the density functional theory (DFT) is employed to analyze the structural, electronic, optical, and hydrogen storage characteristics of double perovskite-type hydrides AOsH (A = Mg-Ba). The reported findings related to the structural aspects are in good agreement with the experimental results. All these compounds exhibit the FCC structure and formation enthalpy H which demonstrate their thermodynamic stability. The estimated band gap values for these compounds are 3.4, 3.0, 2.43, and 1.86 eV respectively by using perovskite-modified Becke-Johnson potential (P-mBJ) plus U parameter. According to the results, as going from Mg to Ba, the band gap decreases because of the increase in atomic radii. Furthermore, all the understudy compounds hold direct band gap nature, and their tuned band gap values show significant agreement with available results on isotropic compounds. The MgOsH is ultraviolet sensitive, and CaOsH, SrOsH, and BaOsH possess excellent optical behavior in the visible region. The characteristic dielectric function, oscillator strength, energy loss function, excitation coefficient, refractive index, reflectivity, and optical conductivity of these double perovskites type hydride indicate that they are highly suitable for optoelectronic applications. However, in terms of hydrogen storage performance, the gravimetric storage capacity of MgOsH is 2.77 wt%, for CaOsH is 2.59 wt%, for SrOsH is 2.15 wt%, and for BaOsH is 1.22 wt% while the favorable desorption temperature for these compounds is 189.46, 220.76, 311.19, and 356.37 K respectively with the formation energy of 24.76, 28.85, 40.67, and 46.58 kJ/mol, which is feasible in actual application.
In the current investigation, the FP-LAPW method is used which is executed in WEIN2k simulation code. The generalized gradient approximation and mBJ with Hubbard U are used to address the exchange and correlation potentials. The Kramar-Kroning relation is used for optical properties assessment. The analytical technique is used to find out the gravimetric hydrogen storage capacity for these compounds while all the plotting was performed using Xmgrace and Origen software.
在本研究中，采用密度泛函理论（DFT）分析双钙钛矿型氢化物AOsH（A = Mg - Ba）的结构、电子、光学和储氢特性。所报道的有关结构方面的研究结果与实验结果吻合良好。所有这些化合物均呈现面心立方（FCC）结构和形成焓H，这表明它们具有热力学稳定性。使用钙钛矿修正的贝克 - 约翰逊势（P - mBJ）加上U参数，这些化合物的估计带隙值分别为3.4、3.0、2.43和1.86电子伏特。结果表明，从Mg到Ba，由于原子半径增加，带隙减小。此外，所有研究的化合物都具有直接带隙性质，并且它们的可调带隙值与各向同性化合物的现有结果显示出显著的一致性。MgOsH对紫外线敏感，而CaOsH、SrOsH和BaOsH在可见光区域具有优异的光学性能。这些双钙钛矿型氢化物的特征介电函数、振子强度、能量损失函数、激发系数、折射率、反射率和光导率表明它们非常适合用于光电子应用。然而，在储氢性能方面，MgOsH的重量储氢容量为2.77 wt%，CaOsH为2.59 wt%，SrOsH为2.15 wt%，BaOsH为1.22 wt%，而这些化合物的有利解吸温度分别为189.46、220.76、311.19和356.37 K，形成能分别为24.76、28.85、40.67和46.58 kJ/mol，这在实际应用中是可行的。
在当前研究中，使用了全势线性缀加平面波（FP - LAPW）方法，该方法在WEIN2k模拟代码中执行。采用广义梯度近似和带有哈伯德U的mBJ来处理交换和关联势。使用克拉默 - 克勒尼希关系评估光学性质。使用分析技术来确定这些化合物的重量储氢容量，而所有绘图均使用Xmgrace和Origen软件进行。
