磁几何阻挫材料羟基氯化钴的中红外光谱特征  

Mid-infrared spectroscopic properties of geometrically frustrated basic cobalt chlorides

作　　者：刘晓东[1,2] 陶万军[1] 郑旭光[2] 萩原雅人 孟冬冬[1] 张森林[1] 郭其新[3] 

机构地区：[1]天津工业大学理学院物理系,天津300160 [2]佐贺大学理工学部物理科学科 [3]佐贺大学理工学部电子与电气工程科和同步辐射光应用研究中心

出　　处：《物理学报》2011年第3期708-714,共7页Acta Physica Sinica

基　　金：天津工业大学博士科研启动项目(批准号:20080033);日本学术振兴会科学研究项目(批准号:Kiban-B19340100);日本文部省特定领域科学研究项目(批准号:Tokutei22014008)资助的课题~~

摘　　要：使用3种光谱仪测量了磁几何阻挫材料羟基氯化钴Co2(OH)3Cl的中红外(4000—400cm-1)吸收光谱,筛选出确信为Co2(OH)3Cl的本征吸收峰数据,结合已知的晶体结构参数,指认了官能团和指纹区相应谱峰的来源.在指认中着重探讨了羟基伸缩振动基频模vOH的具体实验数据,根据固体中氢键的特点,以Co3—O平均距离为基准,推算了本样品Co3—OH集团的"自由"vOH,并以此为参考数值,得到了156cm-1的本征红移,从理论上确认了本质上不可忽略的弱氢键的存在,继而发现了本物质中存在晶体材料领域极少有人报道的三聚氢键,即一个Cl离子受体与三个独立的羟基给体形成基本对称的3个氢键,并建议性地指出了该氢键的重要性所在.Three types of FTIR spectrometers were employed to measure the mid-infrared （4000—400 cm-1） absorption spectra of geometrically frustrated hydroxyl cobalt chloride Co2（OH）3Cl,and the intrinsic absorption peaks in the functional group region and fingerprint region were selected and assigned to corresponding vibrational modes according to its known crystal structure. In the assigning process,great emphasis was laid on analyzing the exact experimental data of hydroxyl stretching vibration mode vOH,that is,estimating the free vOH of the Co3—OH group without any hydrogen bond （H-bond）,to obtain the red-shift which reflects the formation of an H-band in Co2 （ OH）3Cl. A 156 cm-1 red-shift is obtained theoretically which demonstrates the presence of non-negligible weak H-bonds,and eventually result in the discovery of the rarely reported trimeric H-bond in the field of crystalline materials,which consists of three independent hydroxyl donors and only one Cl-acceptor. We explained the relative weakness of this kind of hydrogen bond which may have a critical effect on the lattice symmetry and magnetic structure.

关 键 词：红外光谱 几何阻挫 羟基氯化钴 三聚氢键 

分 类 号：O482.3[理学—固体物理]