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NAMs中缺陷—OH红外吸收的温度依赖行为研究

发表时间:2010-11-15  浏览量:1672  下载量:470
全部作者: 杨燕,夏群科
作者单位: 中国科学院壳幔物质与环境重点实验室,中国科学技术大学地球和空间科学学院
摘 要: 利用原位变温红外光谱实验手段,测得单斜辉石(clinopyroxene,Cpx)、斜方辉石(orthorhombic pyroxene,Opx)和长石(feldspar)中结构羟基从25℃间隔100℃升高到500℃时每个温度下的红外吸收光谱。结果表明:当温度恢复到25℃时,红外谱图的变化是可逆的。单斜辉石和斜方辉石的3组—OH吸收峰的伸缩振动频率都随温度的升高而降低,并且3组峰均表现出不同的温度依赖性。然而,长石位于3 200 cm-1处的宽峰随着温度的升高而向高波数移动。—OH波数随温度变化的幅度和方向与初始峰位有关。无论辉石还是长石,随着温度的升高,—OH基频伸缩吸收峰的峰高和峰面积一致降低。矿物中不同的吸收峰有着不同的温度依赖性,但是总的吸收面积都是随温度升高而减小的,但是吸收面积随温度变化的幅度与矿物种类有关。
关 键 词: 地球化学;红外光谱;变温;辉石;长石
Title: Temperature dependence of IR absorption of —OH defects incorporated in NAMs
Author: YANG Yan, XIA Qunke
Organization: Key Laboratory of Crust-Mantle Materials and Environments, Chinese Academy of Sciences, School of Earth and Space Science, University of Science and Technology of China
Abstract: The behavior of structural oxhydryl (—OH) in clinopyroxene (Cpx), orthopyroxene (Opx) and plagioclase (Pl) during successive heating has been investigated by in-situ micro-FTIR measurements under temperatures ranging from 25℃ to 500℃ at 100℃ increment. The results suggest the IR spectra are reversible when the temperature reverses to 25℃. Both Cpx and Opx exhibit a decrease in the three groups of —OH stretching vibration frequency with increasing temperature, and the three groups of —OH band have different temperature shifts. However, Pl very broad band centered at about 3 200 cm-1 shifts to higher frequency with increasing temperature. The value and direction of the —OH frequency shifts dν/dT are in associated with initial wavenumber. Whether pyroxene or plagioclase, increasing temperature leads to a general decrease in the peak height and peak area of —OH fundamental stretching vibration. Different bands exhibit different temperature response in a mineral, while the total —OH absorption area decreases with temperature increasing. But the varying area value with temperature dA/dT is associated with mineral types.
Key words: geochemistry; infrared spectrum; varying temperature; pyroxene; feldspar
发表期数: 2010年11月第21期
引用格式: 杨燕,夏群科. NAMs中缺陷—OH红外吸收的温度依赖行为研究[J]. 中国科技论文在线精品论文,2010,3(21):2168-2172.
 
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