摘要
利用拉曼光谱和红外光谱研究了方解石、白云石和菱镁矿的光谱学特征,探究了影响三种矿物红外辐射性能的因素。三种矿物的拉曼光谱(Raman)、中红外吸收光谱(MIR)、远红外吸收光谱(FIR)显示随着矿物中镁含量的增大将会影响CO_(3)^(2-)的面外弯曲振动(ν_(2))、反对称伸缩振动(ν_(3))和平面内弯曲振动(ν_(4)),使各光谱特征峰均向高频端迁移。基于黑体辐射定律以及在80℃、400~2000 cm^(-1)矿物的辐射能量谱,结果显示方解石、白云石、菱镁矿的发射率依次减少(0.951,0.938,0.895)。三种矿物的红外吸收光谱和发射光谱中的振动位置均受CO_(3)^(2-)基频的显著影响,在1300~1650 cm^(-1)均产生宽的低吸收带,该吸收带与CO_(3)^(2-)的反对称伸缩振动相关,且吸收带范围(202,236,272 cm^(-1))与发射率之间呈负相关关系。因此,当最强化学键的振动出现在发射光谱窄的吸收带范围内会产生相对较高的辐射能和发射率。此外,矿物的晶体结构也会影响发射率,大的离子半径、键长和晶胞体积将降低辐射过程中能量的吸收,增强辐射特性。综上研究结果,方解石、白云石和菱镁矿的拉曼光谱和红外光谱揭示了金属原子的相对质量对光谱学特征的显著影响,其发射率可能受到C-O键的反伸缩振动范围、最强吸收带控制的最低发射率以及矿物晶体结构的共同影响。这项研究呈现了必要的光谱信息和热发射率数据以识别特定的碳酸盐矿物,为类似矿物的光谱特征研究奠定了基础;同时为进一步认识地壳中大量的碳酸盐矿物提供了研究方法,也为地外勘探的深入研究给予相关的理论基础。
We used Raman and infrared(IR)spectroscopy in this study to investigate the spectral characteristics and infrared emission performance of calcite,dolomite and magnesite.We found substituting Mg for Ca would influence symmetric stretch(ν_(1)),out-of-plane bend(ν_(2)),asymmetric stretch(ν_(3))and inplane bend(ν_(4))of CO_(3)^(2-) and cause blue shift in all characteristic vibration bands in Raman,mid-IR absorption,far-IR absorption and IR emission spectra.According to blackbody radiation theory and radiation energy spectra of samples in the range of 400 to 2000 cm^(-1)at 80℃,we found the emissivities of calcite,dolomite and magnesite were 0.951,0.938,0.895,respectively.The positions of vibration bands in the infrared absorption/emission spectra of the three minerals are significantly affected by the fundamental frequency of CO_(3)^(2-).All minerals produce a broad low absorption band in the 13001650 cm^(-1)range,which is related to asymmetric stretching of CO_(3)^(2-).Moreover,there is a negative correlation between the C-O absorption range(202,236,272 cm^(-1))and emissivity.Therefore,when the strongest chemical bond vibration gives rise to narrow absorption band in the emission spectrum,relatively high radiation energy and emissivity are indicated.Besides,the mineral crystal structure can also affect emissivity.Larger ionic radius or unit cell volume and longer bond length can reduce absorption energy thus enhance radiation emission in the radiation process.In conclusion,the atomic mass of cations in carbonate minerals can affect Raman and infrared vibrational frequency,and emissivity may be associated with C-O low-absorption band range,crystal structure and strongest absorption band controlling lowest emissivity.This study presents the necessary spectral information and thermal emissivity data for the characterization of carbonate minerals,which provides a reference for the spectroscopic characterization of similar minerals as well as establishes a basis for the characterization of carbonate minerals from t
作者
朱莹
黎晏彰
鲁安怀
丁竑瑞
李艳
王长秋
ZHU Ying;LI Yanzhang;LU Anhuai;DING Hongrui;LI Yan;WANG Changqiu(Beijing Key Laboratory of Mineral Environmental Function and Ministry of Education Key Laboratory of Orogenic Belts and Crustal Evolu-tion,School of Earth and Space Sciences,Peking University,Beijing 100871,China)
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2022年第1期459-469,共11页
Earth Science Frontiers
基金
国家重点研发计划项目(2019YFC1805900,2019YFC1805901)
国家自然科学基金项目(91851208)。
关键词
碳酸盐矿物
中红外吸收光谱
远红外吸收光谱
热红外发射光谱
晶体结构
发射率
carbonate minerals
mid-infrared absorption spectroscopy
far-infrared absorption spectroscopy
infrared emission spectroscopy
crystal structure
emissivity
