Theoretical infrared signature of OH defects in Fe3+, Cr3+ and Al3+-doped enstatite

IF 1.2 4区地球科学 Q4 MATERIALS SCIENCE, MULTIDISCIPLINARY

Physics and Chemistry of Minerals Pub Date : 2024-07-20 DOI:10.1007/s00269-024-01289-2

Etienne Balan, Jannick Ingrin

引用次数: 0

Abstract

The infrared spectroscopic properties of selected defects involving one proton and one nearby M³⁺ (M = Al, Cr, Fe) substitution in orthoenstatite are investigated by first-principles calculations. Based on the theoretical results, the absorption bands experimentally observed on synthetic samples with high crystalline quality and low doping levels can be assigned to specific defect configurations. Most of them correspond to Mg vacancies at M2 sites locally compensated by one proton and one M³⁺ cation at a nearby M1 site. This confirms that the M³⁺ + H⁺ = 2 Mg²⁺ exchange mechanism is the dominant hydrogen incorporation mechanism at the lowest concentration levels in doped enstatite. At higher concentration levels, more complex incorporation mechanisms could become dominant in Al-bearing samples.

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掺杂 Fe3+、Cr3+ 和 Al3+ 的芒硝中 OH 缺陷的理论红外特征

通过第一原理计算，研究了正沸石中涉及一个质子和一个邻近 M3+（M = Al、Cr、Fe）取代的选定缺陷的红外光谱特性。根据理论结果，在结晶质量高、掺杂水平低的合成样品上实验观察到的吸收带可归属于特定的缺陷构型。它们大多对应于 M2 位点上的镁空位，由附近 M1 位点上的一个质子和一个 M3+ 阳离子局部补偿。这证实了 M3+ + H+ = 2 Mg2+ 交换机制是掺杂磷灰石中最低浓度水平的主要氢掺入机制。当浓度水平较高时，更复杂的掺入机制可能会在含铝样品中占据主导地位。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Physics and Chemistry of Minerals 地学-材料科学：综合

CiteScore

2.90

自引率

14.30%

发文量

审稿时长

3 months

期刊介绍： Physics and Chemistry of Minerals is an international journal devoted to publishing articles and short communications of physical or chemical studies on minerals or solids related to minerals. The aim of the journal is to support competent interdisciplinary work in mineralogy and physics or chemistry. Particular emphasis is placed on applications of modern techniques or new theories and models to interpret atomic structures and physical or chemical properties of minerals. Some subjects of interest are: -Relationships between atomic structure and crystalline state (structures of various states, crystal energies, crystal growth, thermodynamic studies, phase transformations, solid solution, exsolution phenomena, etc.) -General solid state spectroscopy (ultraviolet, visible, infrared, Raman, ESCA, luminescence, X-ray, electron paramagnetic resonance, nuclear magnetic resonance, gamma ray resonance, etc.) -Experimental and theoretical analysis of chemical bonding in minerals (application of crystal field, molecular orbital, band theories, etc.) -Physical properties (magnetic, mechanical, electric, optical, thermodynamic, etc.) -Relations between thermal expansion, compressibility, elastic constants, and fundamental properties of atomic structure, particularly as applied to geophysical problems -Electron microscopy in support of physical and chemical studies -Computational methods in the study of the structure and properties of minerals -Mineral surfaces (experimental methods, structure and properties)