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首页> 外文期刊>Spectrochimica acta, Part A. Molecular and biomolecular spectroscopy >Fourier transform infrared spectroscopy study of nanostructured nickel oxide
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Fourier transform infrared spectroscopy study of nanostructured nickel oxide

机译：纳米结构氧化镍的傅里叶变换红外光谱研究

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Nanostructured nickel oxide having different average particle sizes ranging from 3 to 16 nm were synthesized and Fourier transform infrared (FTIR) spectra of the samples were recorded in the far infrared (IR) region. The spectra were found to be dominated by surface mode absorptions with no distinct absorption corresponding to the bulk transverse optical mode. IR absorption coefficient, alpha, for the nanostructured NiO samples were calculated as a function of frequency using a macroscopic approach devised by Fuchs. The effects of crystalline geometry, numerical values of optical constants, filling factor and increased damping on the spectral features of the samples were analyzed. Though the simulations approximately reproduced the occurrence of a shoulder in the experimental spectra, the most intense peak in the simulated spectra was found to be about 50 cm(-1) above the corresponding experimentally observed peak. It was shown that the experimentally observed absorption maximum of all the samples were in close agreement with that determined using a microscopic theory based on the rigid ion model. The weak absorption peaks in the frequency region 60-100 cm(-1) appearing in the spectra of all the samples were identified as surface induced transverse acoustical modes, COTA, which became IR active due to the breakdown of translational symmetry in the nanocrystallites. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 42]
机译：合成具有3至16nm的不同平均粒径的纳米结构的氧化镍，并在远红外（IR）区域中记录样品的傅立叶变换红外（FTIR）光谱。发现光谱由表面模式吸收主导，没有对应于本体横向光学模式的明显吸收。使用Fuchs设计的宏观方法，将纳米结构NiO样品的IR吸收系数α作为频率的函数进行了计算。分析了晶体几何形状，光学常数的数值，填充因子和增加的阻尼对样品光谱特征的影响。尽管模拟大致重现了在实验光谱中出现的肩峰，但在模拟光谱中发现的最强烈峰比相应的实验观察到的峰高约50 cm（-1）。结果表明，所有样品的实验观察到的最大吸收值与使用基于刚性离子模型的微观理论确定的最大吸收值非常接近。在所有样品的光谱中出现的60-100 cm（-1）频率区域中的弱吸收峰被确定为表面诱导的横向声模COTA，由于纳米微晶中平移对称性的破坏，COTA变为IR活性。 （C）2002 Elsevier Science B.V.保留所有权利。 [参考：42]

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