【作者】 凌宗成；

【导师】 夏海瑞； 王阿莲；

【作者基本信息】 山东大学 ， 凝聚态物理及行星科学， 2008， 博士

【摘要】 从身边美丽的人工激光晶体到遥远的月球和火星土壤,本论文涉及的内容穿越了时空的距离。而有一条红线贯穿它们,那就是无机晶体的光谱学。本论文作者于2006年12月受山东大学资助赴美国华盛顿大学学习,从而由原来的凝聚态物理转到了行星科学这个方向。此前作者一直在夏海瑞教授的指导之下进行钨酸盐晶体的光谱学研究。在美国学习的一年时间里,作者在王阿莲教授的指导下进行了月壤和火星硫酸盐的光谱学研究。1.钨酸盐激光晶体光谱和热学特性激光自诞生至今已经经历了近50年的时间。这期间,激光的应用已经深入到人们生活的各个角落,在包括光信息存储、光纤通信、医疗等领域展现了广阔的应用前景。激光晶体是固体激光器的主要工作介质之一。如今,一系列的钨酸盐晶体包括KGd（WO₄）₂,CaWO₄和BaWO₄等晶体,因为具有很大的三阶非线性系数x³,使得它们有潜力成为高效的受激喇曼介质,而受到人们越来越多的关注。由于掺Yb³⁺的激光晶体能级结构简单、量子效率高、光转换效率高、荧光寿命长等优点,使其在超短脉冲激光领域有着广泛的应用。掺Yb³⁺的钨酸盐激光晶体具有很高的吸收和发射截面及宽的发射波长范围,因而在超短脉冲激光方面越来越收到重视。此外,掺Yb³⁺的钨酸盐晶体还可以用于自喇曼激光的输出。我们对三种典型结构的钨酸盐激光晶体SrWO₄、Yb:KLu（WO₄）₂（Yb:KLuW）和Yb:NaGd（WO₄）₂（Yb:NGW）进行了系统的晶体振动光谱研究和热学性能研究。主要内容包括:1)大尺寸高质量的SrWO₄单晶利用提拉法生长而成。利用C_4h⁶（I4₁/α）空间群对其进行了晶体振动模式分类。对其进行了全面的偏振喇曼光谱和红外吸收光谱测试,取得了与理论分析相一致的结果。晶体振动谱的实验结果表明,SrWO₄晶体的振动谱主要源于WO₄四面体的内振动模式,部分源于SrO₈的外振动模式。两个最强的喇曼峰位于923 cm^-1（v₁）和841cm^-1（v₃）,对应于WO₄四面体的对称伸缩和反对称伸缩振动。它们的半峰宽很窄,可作为稳态受激喇曼散射的谱线。全面测试了晶体的比热、热膨胀、热扩散性质并计算了晶体的热导率。SrWO₄晶体的比热在333.15 K至1063.15 K温度范围内变化不大,处于0.30～0.34 J·g^-1·K^-1范围内,且与杜隆-珀替定律符合较好。在373.15到1173.15K内的平均热膨胀系数分别为α_a=5.1×10^-6/K,α_b=5.4×10^-6/K,α_c=17.2×10^-6/K,c向的热膨胀是a向的3倍多,这表明SrWO₄晶体的热膨胀各向异性较强;晶体沿a向的热导率比c方向要好一些,但其室温热导率的比值为k_a/k_c=1.06,这说明SrWO₄晶体的热导率各向异性较小。我们从其结构和与晶体振动谱关联的角度对热膨胀和热导率各向异性进行了解释,发现Sr原子引起的晶体外模振动对于晶体的热导率性能的影响较大。从晶体热学性能特别是热导率性能角度来看,SrWO₄晶体是一种很有前途的喇曼激光晶体。2)5%Yb³⁺离子掺杂的KLuW晶体利用顶部籽晶法生长成功。利用空间群C_2h⁶(C_2/c)对其进行了振动模式分析,理论预测了可能出现的喇曼峰和红外吸收峰。利用偏振喇曼光谱和傅立叶变换红外透过谱全面研究了该晶体的晶格振动特性。晶体中全对称类的振动模主要归于WO₆八面体的六个内振动模。我们在喇曼实验中发现了一个原本喇曼非活性的模v₆模。Yb:KLuW晶体的908cm^-1（v₁）和756cm^-1（v₃）的线宽分别为12.5cm^-1和16.6cm^-1,相应的声子弛豫时间分别为849.4 fs和639.6 fs,这预示着该晶体是一种非常有潜力的自喇曼激光晶体。对Yb:KLuW晶体的热学性质进行了全面的表征。在温度范围为303.15 K至723.15 K,Yb:KLuW晶体的比热比SrWO₄晶体小,在0.27 Jg^-1K^-1至0.32 Jg^-1K^-1之间,且符合杜隆-珀替定律。我们测得了在323.15 K至723.15 K之间,Yb:KLuW晶体沿四个已知方向a,b,c,a^*的热膨胀系数,并计算了晶体沿主轴方向的热膨胀系数,分别为α_Ⅰ=8.366×10^-6/K,α_Ⅱ=3.2×10^-6/K,α_Ⅲ=14.934×10^-6/K,得到了热膨胀率椭球,最大的热膨胀主轴α_Ⅲ的方向与晶体学c向夹角很小,仅4.134°,热膨胀最大的α_Ⅲ轴可以达到热膨胀系数最小的b向（α_Ⅱ）的4倍多。由此可见,Yb:KLuW晶体具有很强的热膨胀各向异性。我们测得了Yb:KLuW晶体沿a,b,c,a^*的热扩散系数,计算了晶体在不同温度下沿主轴方向的热扩散系数和热导率,并得到了常温下的热导率椭球。最大的热膨胀主轴k_Ⅲ的方向与晶体学c方向夹角为34.4°。常温下的主轴热导率分别为,k_Ⅰ=2.698 Wm^-1K^-1,k_Ⅱ=2.361 Wm^-1K^-1,k_Ⅲ=4.225 Wm^-1K^-1。Yb:KLuW晶体的热导率也具有很大的各向异性,k_Ⅲ轴方向是k_Ⅱ轴（b）方向的近2倍。我们从晶体结构的角度及其与晶体振动谱之间的关联,讨论了这种各向异性的起源。根据我们的晶体振动谱的研究,特别是偏振喇曼光谱的研究表明,Yb:KLuW晶体是一种很有潜力的自喇曼激光晶体。3)通过提拉法生长大尺寸的Yb:NGW单晶。我们采用空间群S₄²（I4）对其进行了振动模式的分类。测量了晶体的偏振喇曼谱和红外吸收谱。晶体中的主要振动模式归于WO₄四面体的内模。我们在喇曼谱中发现一个新的喇曼峰,将其归于E模的异常声子方向色散,这揭示了晶体是一种没有对称中心的晶体,也从一个方面说明了采用I4进行空间群分析的可行性。Yb:NGW晶体的喇曼谱线相比SrWO₄和Yb:KLuW晶体强度减小,谱峰展宽。特别是对919cm^-1（v₁）和814cm^-1（v₃）两个喇曼峰而言,它们的线宽很大,可以分别达到22.2和42.3cm^-1,有望用于瞬态受激喇曼散射。我们对Yb:NGW晶体的热学性质进行了全面的表征:温度为323.15K至1073.15K时,Yb:NGW晶体比热范围为0.35 Jg^-1K^-1～0.58 Jg^-1K^-1,比SrWO₄和Yb:KLuW晶体大一些。在323.15K至723.15K范围内晶体的平均热膨胀系数分别为,α_a=9.30×10^-6,α_c=19.21×10^-6K^-1,沿c向的热膨胀系数是a向的2倍多,显示出一定的热膨胀各向异性,但比SrWO₄和Yb:KLuW晶体要小一些。Yb:NGW在303.15K,Yb:NGW晶体沿a向和c向分别为热导率为1.102 Wm^-1K^-1和1.250 Wm^-1K^-1,比SrWO₄和Yb:KLuW晶体小很多,各向异性较小,且随着温度的升高变化不大。我们从晶体结构和晶体振动谱的角度对其进行了解释。Yb:NGW晶体的喇曼谱线宽很大,这使得其在飞秒激光和调谐激光领域有潜在的应用价值。2.四种典型Apollo月壤的光谱学和矿物化学研究随着月球探索新浪潮的到来,利用现代化的新技术方法对Apollo Missions（USA）和Luna Missions（USSR）采集的样品进行进一步特征化是极有必要的。近年来行星激光喇曼光谱仪及光谱学的发展极其迅速。与传统使用于行星科学的可见-近红外或中红外热辐射光谱学相比,激光喇曼光谱学的最大特点是它可以为行星表面物质提供最确切的矿物学信息,包括矿物相鉴定、岩石和土壤的矿物模式组成和主要矿物的化学特征等。因此近年来一直为国际行星科学界视为行星（月球,火星,金星,小行星等）表面无人登陆探测车的最热门科学负载之一。矿物的自发喇曼光谱提供晶体基频振动模式中喇曼活性振动谱带。与其相应,中红外光谱可以提供满足红外选择定则的基本振动模谱带。而可见-近红外光谱（Vis-NIR）,作为行星轨道遥感的传统手段,则提供倍频、组和频以及电子转移模的一些信息。三种光谱学方法相结合可以从原子分子量级提供月球样品的确切矿物学信息和主要化学信息。更重要的是,它们可以协助建立月球表面原位探索和月球轨道遥感之间的直接联系。本项研究的主要内容是利用激光喇曼光谱、中红外、可见-近红外反射光谱来研究四种典型Apollo月壤的矿物组成和化学组成。我们选择了Apollo 14163、15273、67513和71501等四种典型阿波罗月壤作为研究对象,主要的研究内容包括:1)估算了四种月壤样品中月壤颗粒粒径。所有四种月壤的粒径分布在10～40μm范围以内。月壤颗粒粒径的大小一定程度上反映了该月壤的成熟度。Apollo 67513粒径最大（～30μm）,它的成熟度最低;而Apollo14163是四种月壤中粒径最小的（10-20μm）,它的成熟度是四种月壤中最高的。2)利用喇曼矩阵测量法估算了各月壤样品中矿物模式组成。在所有四种月壤中,斜长岩是含量最多的矿物。其在Apollo 67513月壤中所占体积分数最大,达到56.6%,而在Apollo 71501含量最小,仅为25.6%。这与四种月壤的取样地点的岩石组成密切相关,即Apollo 67513取样于NorthRay Crater附近的富铁钙长岩含有最多的斜长石,而Apoll071501取样于Tarrus Valley中部的月海玄武岩区域。因此,Apollo 67513中的斜长石含量比Apollo71501高很多。在Apollo 67513中斜方辉石的含量比单斜辉石的含量多,而Apollo 71501中则相反,单斜辉石的含量比斜方辉石多。在Apollo 14163中斜方辉石比单斜辉石稍多,而在Apollo15273中两种辉石的含量相当。另外,我们在Apollo 14163和Apollo 15273中还发现了石英。利用喇曼光谱对月壤中的斜长石进一步分类可以发现,Apollo67513中的长石91%是低温钙长石,Apollo14163和15273月壤中富钠钙长石的含量较多。冲击钙长石在67513中含量很少,这一定程度上反映了该月壤的成熟度较其他月壤低。3)对所测辉石和橄榄石的喇曼光谱进行光谱拟合,获得精确的谱峰位置数据,然后计算出辉石中Mg/（Mg+Ca+Fe）和Ca/（Mg+Ca+Fe）以及橄榄石中Mg/（Mg+Fe）,得到了四种月壤中辉石和橄榄石的矿物化学特征信息。Apollo 67513月壤中的辉石富含镁,而Apollo71501中的辉石含铁较多,而且Apollo71501中普通辉石要比易变辉石要多。Apollo 14163计算结果中可信度较高的点大都处于易变辉石的区域。Apollo15273中辉石分布区域最大,数据点分散,这也一定程度上反映了该月壤源区的岩石比较复杂。这一点也可以从辉石中Mg/（Mg+Ca+Fe）频率分布图可以可以看出。Apollo 67513来自于典型的高地斜长岩和苏长岩为主,Apollo 71501是月海玄武岩成分为主,Apollo 14163是KREEP岩石为代表的成分,而Apollo15273可以看做这三种典型岩石的混合组成,所以来源成分最为复杂。这四种土壤的成分都与局域的岩石成分比较接近,因此局域月岩风化成为它们的主要来源。4)从四种月壤的中红外光谱可以发现Apollo 67513具有比较尖锐的红外光谱。相比之下,其他三种月壤的谱带很宽,这表明它们的结晶性较差,因而具有相对较高的成熟度。在近红外漫反射谱上,我们还发现了所有月壤样品都吸附了一定量的水,而不同的月壤的水峰位置不同。四种月壤的中红外谱中均出现了用于月壤保存的teffron塑料的特征峰。5)从可见近红外反射光谱来看,Apollo 67513具有最高的反照度,位于938nm吸收是由于其中的斜方辉石引起。这与喇曼矩阵测量获得的矿物组成结果一致,即斜方辉石的含量较高。1330nm处的吸收是其中富含的斜长石引起的。Apollo 14161,15273和71501的光谱对比度比Apollo67513要小很多,这反映了它们较高的成熟度。3.火星硫酸盐研究:含水硫酸铁的光谱学和稳定场通过轨道遥感（OMEGA,CRISM）和火星表面探测（Viking,Mars Pathfinder,Mars Exploration Rovers）,大量的硫酸盐已在火星上被发现。轨道遥感发现了火星上存在硫酸镁和硫酸钙的证据,但却没有发现硫酸铁。然而精神号和机遇号火星车则在两个着陆地点附近发现了硫酸铁存在的确凿证据。关于火星的含水硫酸铁仍然有很多未解之谜,特别是详细的矿物组成,含水状态、起源、火星表面条件下的形成机制以及硫酸盐在当前火星水循环中的作用和火星水文历史中的角色等。我们实验室合成了一系列含水硫酸铁,对其进行了系统的X射线物衍射物相分析、喇曼光谱、中红外光谱、可见近红外光谱的分析。然后我们选取其中的5种含水硫酸铁作为起始反应物,开始研究它们在3种不同温度和10种不同湿度下的相变过程和稳定场。主要内容包括:1)采用相对湿度控制法获得了七种硫酸铁。它们分别是高铁叶绿矾、板铁矿、副针绿矾、七水铁矾、六水铁矾、五水铁矾和三笠石。其中六水铁矾是一种新型的含水硫酸铁,它的X射线衍射光谱在PDF2006中没有匹配的光谱,经过质量损失计算和喇曼光谱的比较,我们判定其为六水铁矾。2)对合成的七种硫酸铁晶体和非晶形五水硫酸铁做了X射线衍射,进行物相分析。我们发现除了副针绿矾和高铁叶绿矾含有少量板铁矿之外,其他样品都是纯度较高的硫酸铁样品。3)系统地测试了这七种硫酸铁晶体、非晶形五水硫酸铁和硫酸铁饱和溶液的喇曼光谱和中红外光谱,并对其进行了指认。各种硫酸铁都表现出不同的喇曼谱特征,因此可以用来原位物相监测。特别是SO₄四面体的v₁峰随着结晶水状态的提高逐渐蓝移,特别适合作含水硫酸铁的原位物相监测。在中红外光谱（ATR）中也发现了同样的蓝移趋势。我们获得了各种硫酸铁的近红外漫反射光谱（1.0-5.0μm）和可见近红外光谱（0.4-2.5μm）。在0.7-1μm区域各种晶态硫酸铁的吸收带会随着结晶水的减少而逐渐蓝移北并且锐化。在1000-2500nm区域七水铁矾和高铁叶绿矾存在三个明显的吸收带,分别位于1428、1920、1995nm和1454、1945、1979 nm。4)开展了非晶形五水硫酸铁、高铁叶绿矾、板铁矿、七水铁矾、五水铁矾共5种起始含水硫酸铁在50℃、21℃、5℃三种不同温度和10种不同湿度下条件下的稳定场实验。实验取得了初步结果。我们发现从稳定性上来讲,非晶形五水硫酸铁最易潮解,且其吸水之后的相变变化最多。其次是板铁矿,很容易潮解。七水铁矾比五水铁矾更容易吸水引起潮解。高铁叶绿矾是这五种含水硫酸铁中稳定性最高的。在稳定场实验中,我们发现了八水铁矾。虽然X射线衍射结果表明八水铁矾和七水铁矾的结构没有大的差别,但是它们却具有不同的喇曼特征谱。非晶形五水硫酸铁中水的含量是可变的。通过稳定场实验我们发现其化学式可以从Fe₂（SO₄）₃·4H₂O一直变化到Fe₂（SO₄）₃·11H₂O。同样的现象也发生在高铁叶绿矾晶体中,在温度50℃,湿度为5.5%RH条件下它可以失去3个结晶水,化学式可以写作Fe_4.67（SO₄）₆（OH）₂·17.1H₂O。X射线衍射无法揭示这种结晶水的减少,但喇曼光谱可以反映其变化。更多还原

【Abstract】 From conceptual modern,nearby laser crystal to ancient,remote lunar and martian soil,the topic of this thesis seems to have made a big jump.However,the spectroscopy of them link all these dramatic things together.The author was supported as a training student between Shandong University and Washington University in St.Louis,where he studied planetary spectroscopy guided by Dr.Alian Wang.Before that,the author’s major interest was spectroscopy of tungstate laser crystal by the guidance of Professor Xia Hairui,and then he did some research on the spectroscopy of lunar soil and Mar’s related ferric sulfates.1)Spectroscopic and Thermal Properties of Tungstates Laser CrystalsIt’s nearly 50 years since the discovery of laser,which have been widely used in our life such as optical storage,optical communications and medical treatment,etc. Nowadays,a series of tungstate crystals including KGdWO₄,CaWO₄,and BaWO₄, etc,have attracting more and more attentions due to their large nonlinear optical susceptibilityχ³,making them to be efficient frequency converters by SRS.The Yb³⁺ doped double tungstates have show their great potential for building practical diode-pumped continuous wave and ultra-short pulsed lasers due to their advantages of simple manifold,broad absorption and emission cross sections,negligible concentration quenching,low thermal load,etc.The first part of this thesis is the systematic investigations of lattice vibration spectra and thermal properties for three typical tungstate laser crystals SrWO₄. Yb:K（LuWO₄）₂（Yb:KLuW）and Yb:NaGd（WO₄）₂（Yb:NGW）.Detailed work as follows,1)Large size SrWO₄ single crystal was grown by Czochralski method.Raman scattering and infrared absorbance spectra measurement was performed to assign the phonons properties of the crystal combined with the help of Space group analysis based on C_4h⁶（I4₁/α）.The experiments show that the characteristic lattice vibrational modes of SrWO₄ arise mainly from the internal vibrations of the WO₄ tetrahedra and partly by the external SrO₈ polyhedra modes.Two of the strongest peaks 923 cm^-1（v₁）and 841 cm^-1（v₃）,which obtain narrow peak width, can be used in steady SRS experiments.Thermal properties including thermal expansion,specific heat,thermal diffusion and conductivities of the crystal were obtained.The specific heat remains almost constant with a value of 0.30-0.34 J·g^-1·K^-1in the temperature range from 333.15 to 1063.15K,which is in compliance with the Dulong-Petit law.The average thermal expansion coefficient in between 373.15 and 1173.15K are as follows,,α_a=5.1×10^-6/K,α_b=5.4×10^-6/K,α_c=17.2×10^-6/K.The value along c is 3 times larger than that of a or b direction, which suggest a large anisotropy of thermal expansion.However,the thermal diffusion and conductivity show small anisotropy as shown by k_a/k_c=1.06.We explained those anisotropies from the viewpoint of crystal structure and its correlation with lattice vibration spectra.The external modes derived from Sr atoms in the crystal play an important role in the thermal expansion and especially the thermal diffusion and conductivity properties.From the point views of lattice vibration and thermal properties,SrWO₄ crystal is a promising candidate for Raman lasers.2)Monoclinic 5at%Yb doped KLuW crystal was sucessfully grown by TSSG. Space group analysis was conducted based on C_2h⁶(C_2/c),which agrees with the results of polarized Raman spectra and infrared spectra.The all-symmetric vibration was ascribed by WO₆ octahedron’s six modes.Due to the large anisotropy of KLuW,the v₆ was observed in the spectra,v₆ is a silent mode due to the selection rule of octahedron,however,in a crystal field,it was activated by the large distortion of octahedrons.As a self-Raman crystal,the linewidth of Raman peaks 908 cm^-1（v₁）and 756cm^-1（v₃）reach to 12.5cm^-1and 16.6cm^-1,with a relaxation time to be 849.4fs and 639.6fs respectively,indicating that it is a promising SRS Raman crystal.The specific heat of Yb:KLuW,which seems lower than that of SrWO₄,varies between 0.27 and 0.32 J·g^-1·K^-1in the temperature range from 303.15 to 723.15K,which also agrees with the Dulong-Petit law.We got the ellipsoid of thermal expansion coefficient for Yb:KLuW.The calculated principal thermal expansion coefficients of Yb:KLuW between 323.15 and 723.15K are:α_Ⅰ=8.366×10^-6/K,α_Ⅱ=3.2×10^-6/K, a_Ⅲ=14.934×10^-6/K.The angle betweenα_Ⅲand c axis is as small as 4.134°and the value ofα_Ⅲis 4 times larger thanα_Ⅱ,which suggests a very large anisotropy of thermal expansion.We got the ellipsoid of thermal expansion diffusion coefficients.At 303.15K.the principal thermal diffusion coefficients of Yb:KLuW are:k_Ⅰ=2.698 Wm^-1K^-1,k_Ⅱ=2.361 Wm^-1K^-1,k_Ⅲ=4.225 Wm^-1K^-1,which also show large anisotropy.Those large anisotropy,which was ascribed by the different link ways of the WO₆ octahedrons.In a word,from our lattice studies especially the polarized Raman measurement,Yb doped KLuW is a promising medium for SRS operations.3)Large size Yb:NGW single crystal was grown by Czochralski method.We conducted the space group analysis on the Space group S₄²（I（?））.Raman scattering and infrared absorbance spectra analysis show that the Raman properties of Yb:NGW can be well explained by the space group I（?）.The characteristic lattice vibrational modes of Yb:NGW arise mainly from the internal vibrations of the WO₄ tetrahedra and partly by the external Na/GdO₈ polyhedra modes.The new Raman peak E（LO）at 698 cm^-1indicate noncentrosymmetrical structure,which in turn confirm the availability of the Space group analysis under space group I（?）. The linewidth of Raman peaks 919cm^-1（v₁）and 814cm^-1（v₃）reach to 22.2 and 42.3cm^-1,indicating a promising transient SRS Raman crystal.Comparing to SrWO₄ and Yb:KLuW,the specific heat is higher with value 0.35 Jg^-1K^-1～0.58 Jg^-1K^-1between 323.15 and 1073.15K;The average thermal expansion coefficient in between 323.15 and 723.15K are as follows,α_a=9.30×10^-6K^-1,α_c=19.21×10^-6K^-1,which show relatively smaller anisotropy than the other two crystals.At 303.15K,the calculated thermal conductivity coefficients of Yb:NGW are 1.102 Wm^-1K^-1and 1.250Wm^-1K^-1along a and c direction,respectively,much smaller than those of SrWO₄ and Yb:KLuW,which could also be interpreted from the viewpoint of crystal structure and its correlation with lattice vibration spectra. From the viewpoints of lattice vibration and thermal properties,Yb:NGW is a promising candidate for the SRS lasers in the femto-second regime.2.Spectroscopy,Mineralogy and Geochemistry Studies on Four Typical Apollo soilsAs we come into a new era for lunar exploration,it will be beneficial to examine the returned Apollo and Luna samples by various modern analytical techniques and newly developed methodologies.Comparing to the Vis-NIR spectra and thermal emission spectra,Laser Raman spectroscopy（LRS）can provide definitive mineralogical information,including mineral identification,mineral proportions,and major mineral chemistry thus is supposed to be one of the best scientific payload for landed planetary missions（for Moon,Mars,Venus,and asteroids,etc）.Mid-IR spectroscopy yields additional information on fundamental vibrational modes under different selection rules.Vis-NIR spectroscopy（commonly used for orbital remote sensing）offers information on overtone and combinational modes,and electronic transition modes.A combination of these three spectroscopic methods will not only provide a comprehensive set of information at atomic and molecular levels of lunar samples,but will also contribute to a direct link between in situ surface exploration and orbital remote sensing.Four endmembers of lunar soils,Apollo 14163,15273, 67513 and 71501,were selected to investigate their mineralogy and geochemistry properties.Detailed work as follows,1)The grains size of four lunar are estimated in the range of 10-40μm,with Apollo 67513 as the coarsest（～30μm）and Apollo 14163 as the finest（10-20μm）.The difference in grain size suggests the distinct maturity of the lunar soils.This agrees with the fact that Apollo 14163 is the most mature and Apollo 67513 as the most fresh soils among the four soils.2)Raman point-counting results indicate that plagioclase is the most abundant mineral in all four soils,with 67513 highest（56.6%）and 71501 lowest（25.6%）. Orthorpyroxene is richer than clinopyroxene in Apollo 67513 and 14163,almost equal in soil 15273 whereas poorer in soil 71501.Further classification fo plagioclase feldspar indicate that,in Apollo 14163 and 15273,the plagioclase is more sodic than the other two.The shocked anorthite is rare in Apollo 67513, which also suggest it as a fresh soil.We also found quartz in Apollo 14163 and 15273.3)We extract the compositional information,i.e.,the Mg/（Mg+Ca+Fe）, Ca/（Mg+Ca+Fe）in pyroxene and Mg/（Mg+Fe）in olivine,from the calibration of their Raman spectra.As shown in the pyroxene quadrilaterals,pyroxene grains in Apollo 67513（fresh anorthositic highland soil）are slightly richer in Mg;whereas in Apollo 71501（high Ti mare soil）,they are slightly richer in Fe with more augite grains than pigeonite.The most reliable points locate in the region of pigeonite for Apollo 14163.For sample 15273,the compositional distribution of pyroxene is scattered more widely than the other three,which suggest the complexity for the source of soil.4)Compared with the ATR spectra of soil 67513,the spectra of soils 14613,15273 and 71501 all have a wide v₃ band with much less spectral detail,which suggests low crystallinity,thus higher soil maturity.Among the four soils,Apollo 67513 has the lowest maturity.Adsorbed water and organic contaminants most likely associated with the Teflon sample containment material are evident in the in the diffusion reflectance spectra.5)The soil 67513 shows the highest albedo in the Vis-NIR region,with a strong orthopyroxene absorption band near 938 nm and plagioclase absorption at 1330 nm.This observation is consistent with Raman analyses,i.e.,a higher proportion of orthopyroxene.Spectra from soil 14163,15273 and 71501 have lower spectral contrast than soil 67513,which is a reflection of their maturity.3.Sulfates on Mars:Systematic Spectroscopic Studies and Stability Field of Hydrous Ferric Sulfates Sulfated have been identified on Mars by orbital missions（OMEGA on Mars Express and CRISM on MRO）and landing missins（Viking,Mars Pathfinder,Mars Exploration Rovers）.However,Orbital observations clearly show evidence for Mg-and Ca-sulfates,but not Fe-sulfates,whereas the MER rovers have found Fe-sulfates at both landing sites.Nevertheless,there are still a large number of unknowns about ferric sulfates on Mars,especially the detailed mineralogy,hydration states,origins, pathways of formation under Mars surface conditions,and their significance to the current water budget on Mars and their role in Mars’ hydrologic history.To address the unknowns related to ferric sulfates on Mars is the aim of this laboratory study.We prepared ferric sulfates in the laboratory and did a systematic characterization of their XRD,Raman,Mid-IR and Vis-NIR spectroscopic properties.After that,we started the stablitly field studies of five ferric sulfates using ten humidity buffers at three temperatures.Detailed work as follows,1)Seven hyedrated ferric sulfates were synthesized by humidity buffer technique. They are ferricopiate,rhomboclase,parqconquimbite,kornelite,lausenite, pentahydrate,and mikasaite.The lausenite is a new phase of hydrated ferric sulfates which we could not find the match of their XRD pattern in PDF 2006 database.By the mass loss calculation and comparing their Raman patter,we tentatively assigned it as lausenit.2)X ray diffraction（XRD）experiments were concucted on all the seven synthetic crystalline ferric sulfates and the amorphous phase（5w）.The phase determintation results show that except for paracoquimbite and ferricopiapite, which containts very small amount of rhomboclase,the other ferric sulfates are pure.3)We have obtained Raman spectra,mid-IR,Vis-NIR（0.4-2.5μm & 1.0-5.0μm） spectra from the seven crystalline ferric sulfates,the amorphous（5w）phase,and the saturated solution.All these ferric sulfates show different Raman features, thus are diagnostic for in-situ phase identifications.The v₁ peak of SO₄ tetrahedra shift to a high frequency as the decrease of the hydration of these ferric sulfates, thus is especially suitable to identify the different hydrated ferric sulfates.Similar tendency appears in their ATR spectra.Kornelite and ferricopiapite show diagnostic features in the NIR region（located at 1428,1920,1995 nm and 1454, 1945,1979 nm,respectively）as indicated by diffuse reflectance spectra and Vis-NIR spectra.However,the water band（～1.9μm）of other ferric sulfates show minor changes.In the 0.7～1μm region of Vis-NIR spectra,the major absorption band of Fe³⁺shows a blue shift and becomes narrower for ferric sulfates with lower hydration degree.Notice the spectra of amorphous ferric sulfates and saturated solution do not follow well with these two trends4)We are conducting a set of experiments on the stability field and phase transition pathways of five ferric sulfates（amorphous（5w）phase,ferricopipiate, rhomboclase,kornelite,pentahydrate）,using ten humidity buffers at 50℃,21℃, 5℃,respectively.The preliminary results show that the deliquescence sequence is as follows,amorphous（5w）＞rhomboclase＞kornelite＞pentahydrate＞ferricopipite. Furthermore,we found a new phase of ferric sulfates,which is 8 water hydrated phase by mass loss calculation.XRD results indicate it was kornelite,however, the Raman pattern is different from kornelite.Similarly,the hydrates state of amorphous phase can be variable from Fe₂（SO₄）₃·4H₂O to Fe₂（SO₄）₃·11H₂O。At 50℃and 5.5%RH,ferricopiapite can lose 3 structural water(can be wirrten as Fe_4.67（SO₄）₆（OH）₂·17.1H₂O).All these changes can be monitored by in Situ Raman spectra but cannot by XRD.更多还原