Cooper Valentino R, Krogel Jaron T, Donald Kelling J
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States.
Department of Chemistry, Gottwald Center for the Sciences, University of Richmond, Richmond, Virginia 23173, United States.
J Phys Chem A. 2021 May 13;125(18):3978-3985. doi: 10.1021/acs.jpca.0c10847. Epub 2021 Mar 16.
The mercury dihalides show a remarkable diversity in the structural preferences in their minimum energy structure types, spanning molecular to strongly bound ionic solids. A challenge in the development of density functional methods for extended systems is to arrive at strategies that serve equally well such a broad range of bonding modes or structural preferences. The chemical bonding and the stabilities of mercury dihalides and the general utility and reliability of the van der Waals density functional with C09 exchange (vdW-DF-C09) in predicting or describing the energetics and structural preferences in these metal dihalides is examined. We show that, in contrast with the uncorrected generalized gradient approximation of the Perdew-Burke-Erzenhoff (PBE) exchange-correlation functional, qualitative and quantitative patterns in the bonding of the mercury dihalide solids are well reproduced with vdW-DF-C09 for the full series of Hg systems for = F, Cl, Br, and I. The possible existence of a low-temperature cotunnite polymorph for HgF and PbF is posited.
二卤化汞在其最低能量结构类型的结构偏好上表现出显著的多样性，涵盖了分子型到强键合离子固体。开发用于扩展体系的密度泛函方法面临的一个挑战是找到能同样适用于如此广泛的键合模式或结构偏好的策略。本文研究了二卤化汞的化学键合和稳定性，以及采用C09交换的范德华密度泛函（vdW-DF-C09）在预测或描述这些金属二卤化物的能量学和结构偏好方面的通用性和可靠性。我们表明，与Perdew-Burke-Erzenhoff（PBE）交换关联泛函的未修正广义梯度近似不同，对于Hg系列（X = F、Cl、Br和I）的整个系列，vdW-DF-C09能很好地重现二卤化汞固体键合中的定性和定量模式。文中推测了HgF和PbF可能存在低温方铅矿多晶型物。
