Hou Chunju, Botana Jorge, Zhang Xu, Wang Xianlong, Miao Maosheng
School of Science, JiangXi University of Science and Technology, Ganzhou, 341000, P. R. China and Beijing Computational Science Research Center, Beijing 100094, P. R. China.
Beijing Computational Science Research Center, Beijing 100094, P. R. China and Department of Chemistry and Biochemistry California State University Northridge, CA 91330, USA.
Phys Chem Chem Phys. 2016 Jun 1;18(22):15322-6. doi: 10.1039/c6cp02627c.
The pressure-induced evolution of AgO crystal structures and the oxygen environment of Ag atoms were investigated by means of density functional theory with a hybrid functional and a structure prediction method. Under ambient conditions, AgO has two nonequivalent Ag1 and Ag2 sites that adopt linear and square planar oxygen environment configuration, respectively, corresponding to Ag mixed-valence states. The results show that both the coordination environment and the valence state of the Ag1 site are sensitive to pressure and will gradually approach those of the Ag2 site as it increases. The band gap also decreases significantly and at 75 GPa AgO experiences a pressure-induced semiconductor-to-metal transition. At ∼77 GPa, there is a structural transition from monoclinic (P21/c) to trigonal (R3[combining macron]m), accompanied by a valence state transition from the mixed-valence state to a single-valence state.
通过采用杂化泛函的密度泛函理论和一种结构预测方法，研究了压力诱导的AgO晶体结构演变以及Ag原子的氧环境。在环境条件下，AgO有两个不等价的Ag1和Ag2位点，分别采用线性和平面正方形氧环境构型，对应于Ag的混合价态。结果表明，Ag1位点的配位环境和价态对压力都很敏感，并且随着压力增加会逐渐接近Ag2位点的配位环境和价态。带隙也显著减小，在75 GPa时，AgO经历压力诱导的半导体到金属的转变。在约77 GPa时，发生从单斜（P21/c）到三角（R3[combining macron]m）的结构转变，同时伴随着从混合价态到单价态的价态转变。
