KH2PO4中电子或空穴辅助下的氢缺陷反应

研究了非线性光学晶体材料KH2 PO4(KDP)中不同带电状态的H缺陷的稳定性及其反应 .从而以清晰的物理图像描绘了KDP材料暴露在强紫外线或X射线下性能下降的原因 .研究发现 ,对于H间隙原子 ,当增加一个电子时 ,H间隙原子与主H原子发生作用 ,形成间隙H2 分子并产生一个H空位 ,而增加一个空穴时H间隙原子与临近的主O原子形成氢氧键 ,这两种带电态的H间隙原子均切断KDP材料中形成网络的氢键 ;对于H空位 ,增加一个空穴将导致形成“过氧化氢”桥结构 .这些结果在原子层次上清楚地解释了实验所建议的缺陷反应机制

Electron-or hole-assisted reactions of H defects in KH2PO4

The stability and defect reactions of neutral and charged H interstitial (H i) and H vacancy (H v) in KH 2PO 4(KDP) have been studied by an ab initio method. The neutral H i does not interact with the host atom; the addition of an electron leads to the ejection of a hydrogen host atom and the subsequent formation of an interstitial H 2 molecule and an H v, whereas the addition of a hole gives rise to the formation of a hydroxyl bond. Thus H i in both charged states severs the H-bonded network. For the H v the addition of a hole leads to the formation of a peroxyl bridge. The results elucidate the underlying atomic mechanism for the defect reactions suggested by the experiment.