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为研究锡砷化合物真空下热分解的机理,对Sn_4As_3和SnAs化合物进行真空条件下热分解的热力学计算,得到它们30 Pa的条件下开始发生反应的温度。采用基于密度泛函理论的平面波赝势法计算得到Sn_4As_3和SnAs的稳定结构,在此基础上用从头算分子动力学的方法模拟了它们在1463 K,30 Pa和1373 K,30 Pa条件下的热分解过程,并计算了Sn_4As_3和SnAs(100)面的热分解。过程计算结果表明,在模拟条件下超胞内砷的脱除可能分步进行,并且更倾向于以As_2的形式分解。表面的Sn-As键比晶胞内部更加容易分离。
In order to study the mechanism of thermal decomposition of tin-arsenic compounds under vacuum, the thermodynamic calculations of the thermal decomposition of Sn_4As_3 and SnAs under vacuum conditions were carried out, and the temperatures at which they started to react under the conditions of 30 Pa were obtained. The stable structures of Sn_4As_3 and SnAs were calculated by the plane wave pseudopotential method based on density functional theory. Based on this, their ab initio molecular dynamics simulations were carried out to simulate the stable structures of Sn_4As_3 and SnAs at 1463 K, 30 Pa and 1373 K, 30 Pa Thermal decomposition process, and calculate the thermal decomposition of Sn_4As_3 and SnAs (100) surface. The calculation results of the process show that the removal of intracellular arsenic may proceed in a stepwise manner under simulated conditions and is more likely to decompose in the form of As 2. The Sn-As bonds on the surface are easier to separate than the interior of the unit cell.