Anomalous bond-length behaviors of solid halogens under pressure

• 作者: Min Wu Ye-Feng Wu Yi Ma
• 来源期刊: 中国物理B（英文版）
• 年，卷（期）: 2021,（7）
• 所属期刊栏目: CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROP-ERTIES
• 页码范围: 477-482
• 页数: 6页
• 语种: 英文
• DOI: 10.1088/1674-1056/abf4bd

摘要

The three halogen solids (Cl2,Br2,and I2) have the isostructural diatomic molecular phase Ⅰ with a space group of Cmca at ambient pressure.At high pressure,they all go through an intermediate phase V with incommensurate structures before eventually dissociating into the monatomic phase Ⅱ.However,a new structural transition between phase Ⅰ and V with anomalous bond-length behavior was observed in bromine under pressure,which,so far,has not been confirmed in iodine and chlorine.Here,we perform first-principles calculations for iodine and chlorine.The new structural transition was predicted to be common to all three halogens under pressure.The transition pressures might be systematically under-estimated by the imperfect van der Waals correction method,but they follow the order Cl2 ＞ Br2 ＞ I2,which is consistent with other pressure-induced structural transitions such as metallization and the molecular-to-monatomic transition.