高压下天然菱铁矿的压缩性和电子结构研究

发布时间：2018-01-10 05:25

本文关键词：高压下天然菱铁矿的压缩性和电子结构研究　出处：《岩石矿物学杂志》2016年02期 　论文类型：期刊论文

【摘要】：采用同步辐射光源和金刚石对顶砧(DAC)技术,对天然菱铁矿的压缩性和电子结构进行了原位X射线衍射(XRD)和X射线吸收近边结构谱(XANES)测试研究。在室温下随着压力逐渐升高至50.2 GPa,菱铁矿保持方解石型结构不变,但是逐渐向Na Cl型结构转变;刚性[CO3]2-基团平行于ab-平面定向排列使c轴的压缩性大于a轴。菱铁矿在44.6~47.1 GPa之间发生电子由高自旋态(HS)向低自旋态(LS)的转变,表现为体积塌陷8%。HS菱铁矿的等温状态方程参数为K0=112(5)GPa和K'0=4.6(3)。首次采用XANES技术对菱铁矿中Fe2+的电子结构进行了研究,结果表明:随着压力升高至37.3 GPa,Fe2+的配位和局域对称并未发生明显变化;此后电子结构开始转变,Fe2+的3d轨道分裂能降低,电子跃迁概率增大,呈现LS特性。
[Abstract]:The technology of synchrotron radiation and diamond anvil was used. The compressibility and electronic structure of natural siderite were studied by in situ X-ray diffraction (XRD) and X-ray absorption near edge structure spectroscopy (XANES). The test results show that the pressure increases to 50.2 GPa at room temperature. The calcite structure of siderite remained unchanged, but gradually changed to NaCl structure. Rigidity. [The compressibility of the c-axis is larger than that of the a-axis due to the directional arrangement of the 2-group parallel to the ab-plane. The electrons in siderite from high spin state to low spin state occur between 44.6 GPa and 47.1 GPa. The transformation of LSs. The isothermal equation of state parameters of the isothermal equation of state of HS siderite are K01125GPA and KG00.4.6GPA). The electronic structure of Fe2 in siderite was studied by XANES technique for the first time. The results showed that the coordination and local symmetry of Fe _ 2 did not change significantly with the pressure increasing to 37.3 GPa-Fe _ 2. Since then, the 3D orbital splitting energy of Fe2 has been reduced and the transition probability of the electron has been increased, showing the LS characteristic.
【作者单位】：北京大学地球与空间科学学院造山带与地壳演化教育部重点实验室;中国科学院上海应用物理研究所;中国科学院高能物理研究所北京同步辐射实验室;
【基金】：国家自然科学基金资助项目(U1232204,41473056)~~
【分类号】：P578.61
【正文快照】： 碳(C)是地球系统的重要元素,随着全球变暖及碳减排问题日益突出,碳循环的研究受到了越来越多的重视。地球系统碳循环包括表层碳循环(大气圈-水圈-生物圈)和深部碳循环(地表系统-壳幔系统)两部分。在地质历史时期,大量深海沉积的碳酸盐经洋壳俯冲作用进入地球内部、再经变质和

【相似文献】