——晶格畸变与化学反应活性的关系
(中南大学 矿物工程系， 长沙 410083)
摘 要: 采用基于密度泛函的规范保持赝势分子动力学方法，模拟了外应力对黄铁矿晶体结构的影响，计算了畸变晶格的能带结构和态密度。计算结果表明：晶格畸变导致费米能级升高；过渡状态理论分析表明机械活化提高了化学反应速率常数，即交换电流密度( J0FeS2, J0O2)增大。根据半导体电化学能带模型和腐蚀电化学混合电位模型，晶格畸变导致晶体费米能级EF升高和交换电流密度增大，从而使黄铁矿腐蚀电流增大，腐蚀速率提高。黄铁矿机械活化内在原因不仅是机械化学机制，更重要的是机械电化学机制。
关键字: 密度泛函理论； 分子动力学； 黄铁矿； 机械活化； 电子结构； 化学反应活性； 机械电化学
mechanical activation of pyrite (Ⅰ)
——Relation of structural strain to
chemistry reaction activity
（Department of Mineral Engineering， Central South University，
Changsha 410083, P.R.China）
Abstract: Effect of external high pressure on crystal structure of pyrite (FeS2) has been simulated by using abinitio norm-conserving pseudo-potential plane wave molecular dynamic method based on density functional theory， within the general gradient density approximation. The calculation of energy band structure and the density of state for strained pyrite shows that structural strain leads to the increase of pyrite Fermi energy (EF). In addition， according to transitional state theory，mechanical activation promotes the rate constant of chemical reaction， which is equivalent to exchange current density in the field of corrosion electrochemistry. According to energy band model of semiconductor and mixed potential model of corrosion electrochemistry， the corrosion current of pyrite increases with the increase of pyrite Fermi energy(EF) and exchange current density， that is， the rate of dissolution increases. Thus it is concluded that the mechanically active phenomenon of pyrite not only involves mechanism of mechanical chemistry， but also mechanism of mechanical electrochemistry.
Key words: density functional theory; molecular dynamics; pyrite (FeS2); mechanical action; electronic structure; reactive activity; mechanical electrochemistry
