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为研究硫在高温、真空下的结构、稳定性与蒸发性质,对气态硫中S1~8进行了高温、真空条件下反应的热力学计算,得到其在1273~2073 K,10 Pa的条件下可能发生反应的吉布斯自由能变。采用基于密度泛函理论中的广义梯度近似计算得到S2~8的基态结构,并采用从头算分子动力学的方法模拟其在高温、真空下经10.0 ps后的结构和稳定性的变化,并计算给出S2分子的蒸发性质。计算结果表明:硫蒸气在高温、真空下主要以S2分子形式存在;且随着温度的升高,较多原子组成的硫分子稳定性降低,更易于生成更少原子组成的硫分子;S2分子在高温、真空下的蒸发性质可近似作为硫蒸气对应蒸发性质实验数据的参考值。
In order to study the structure, stability and evaporation properties of sulfur under high temperature and vacuum, the thermodynamic calculation of the reaction of S1 ~ 8 in gaseous sulfur under high temperature and vacuum conditions was carried out. Under the conditions of 1273 ~ 2073 K, 10 Pa The Gibbs freedom of reaction changes. The ground state structure of S2 ~ 8 was calculated by generalized gradient approximation based on density functional theory. The structure and stability of S2 ~ 8 were simulated by using ab initio molecular dynamics method under 10.0 ps. The evaporation properties of S2 molecules are given. The results show that the sulfur vapor mainly exists in the form of S2 molecule under high temperature and vacuum. With the increase of temperature, the stability of the sulfur molecules with more atoms decreases and the sulfur molecules with fewer atoms are easier to be generated. The S2 molecule The evaporation behavior at high temperature and under vacuum can be approximated as a reference for experimental data on the vaporization properties of sulfur vapor.