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arXiv 1301.0630cond-mat.str-elcond-mat.mtrl-sci
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稀土与重金属颜料及其颜色的第一性原理

Rare-Earth vs. Heavy Metal Pigments and their Colors from First Principles

Jan M. Tomczak, L. V. Pourovskii, L. Vaugier, A. Georges, S. Biermann

摘要:

许多无机颜料含有对健康和环境有害的重金属。人们把大量注意力放在寻求以稀土元素为基础的无毒替代品上。然而,从第一性原理计算颜色对电子结构方法是一个挑战,特别是对于具有局域f轨道的材料。在这里,仅从原子位置开始,我们计算红色颜料氟硫化铈CeSF以及硫化汞HgS(经典的“朱红色”)的颜色。我们的方法采用多体理论来计算光吸收,结合中间长度尺度建模来评估着色如何取决于膜厚度,颜料浓度和粒度。我们介绍了一种颜料性能的定量标准。虽然对于HgS,由于宽带之间的大的过渡矩阵元素,这个标准是满足的,CeSF提出了一个替代的范例:明亮的红色显示源于准二维性和4f-状态的局部性质的综合效应。我们的工作展示了现代计算方法的力量,并对具有特定光学性质的材料的理论设计产生了影响。

英文摘要:

Many inorganic pigments contain heavy metals hazardous to health and environment. Much attention has been devoted to the quest for non-toxic alternatives based on rare-earth elements. The computation of colors from first principles is a challenge to electronic structure methods however, especially for materials with localized f-orbitals. Here, starting from atomic positions only, we compute the color of the red pigment cerium fluorosulfide CeSF, as well as of mercury sulfide HgS (classic "vermilion"). Our methodology employs many-body theories to compute the optical absorption, combined with an intermediate length-scale modelization to assess how coloration depends on film thickness, pigment concentration and granularity. We introduce a quantitative criterion for the performance of a pigment. While for HgS this criterion is satisfied due to large transition matrix elements between wide bands, CeSF presents an alternative paradigm: the bright red color is shown to stem from the combined effect of the quasi two-dimensionality and the localized nature of 4f-states. Our work demonstrates the power of modern computational methods, with implications for the theoretical design of materials with specific optical properties.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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