Application of Raman spectroscopy in the nondestructive analyses of ancient Chinese jades

Jade, as one of the symbols of Chinese material cultures, is the cultural boundary between ancient Chinese and western civilizations. Amphibole, serpentine, turquoise and quartz are the four main kinds of ancient Chinese jades. In this article, the use of Raman spectroscopy in the nondestructive identification of the four kinds of Chinese jades for their phase is discussed. The spectra, in combination with PIXE analysis, help resolve some relevant and further problems. Copyright © 2010 John Wiley & Sons, Ltd.     

辽宁岫岩河磨玉和老玉(闪石玉)中石墨包体的拉曼光谱及其应用

辽宁岫岩是中国新石器时期红山文化玉器的重要来源,辽宁岫岩的闪石玉可分为河磨玉(籽料)和老玉(山流水和山料)两种。文章利用拉曼光谱技术对两种玉料中发现的石墨包体进行了测试分析。结果显示,两种玉料中石墨包体拉曼光谱的特征明显不同,反映了两类闪石玉形成条件上存在的差异,它们是不同成矿期次或者是不同成矿部位的产物。显然,拉曼光谱技术可以成为无损鉴定玉料产地来源的重要辅助手段。     

拉曼光谱技术在中国古玉、古玉器鉴定和研究中的应用

激光拉曼光谱技术是应用于科技考古研究中的高技术之一,属于无损分析研究,但作为一种很好的无损分析方法它在中国古代玉器研究中的应用并不非常广泛。文章首先介绍了激光拉曼光谱技术的基本原理及近几年来国内外的最新进展,然后从矿物结构与拉曼特征峰之间的关系入手比较了目前国内外5种常见玉石的激光拉曼研究结果。然后分别通过对浙江良渚遗址和河南安阳殷墟遗址出土的4件中国古代玉器与新疆和田地区出产的软玉样品进行对比研究,成功地利用激光拉曼光谱技术对一批中国古代玉器进行了无损鉴定,从而阐明该项技术在中国古代玉器结构测试和材质鉴定中是一种很好的无损分析研究方法。最后,讨论了目前激光拉曼光谱技术在中国古玉和古代玉器研究中存在的局限性并对其发展前景进行了展望。     

液晶稳态和瞬态多波混频与非线性光学特性

在掺杂（～3%重量比）碳纳米管和光敏取向基团的向列态液晶薄膜（5μm厚）中，在使用Ar⁺(514.5nm)为激发光做前向多波混频实验时，观察到7级的自衍射和探测光He-N e(632.8nm )的多级衍射均呈多环状结构.高斯光束中心处的光致非线性折射率系数δn～0.8. Ar⁺ (514.5nm)连续光形成光栅的时间和弛豫时间都与写入光的偏振态强烈相关.在使用Nd :YAG（532 nm）为激发光时，光栅的弛豫时间～200ms量级，且探测光He-Ne(632.8nm)的o光和e光所探 测到的动力学响应曲线是不同的. 关键词： 瞬态 稳态 多波混频 液晶     

Raman scattering and luminescence of yttria nanopowders and ceramics

We have studied Raman scattering in yttria nanopowders and ceramics that was excited by radiation at wavelengths of 514.5 and 632.8 nm. We show that, in undoped nanopowders and cubic phase of doped yttria ceramics, only the Raman scattering by phonons is observed, with no other Raman scattering centers having been revealed. In nanopowders of the monoclinic phase, we have observed an additional Raman line with a Raman shift of 1093 ± 4 cm^?1. If all the objects under investigation are excited by the radiation at a wavelength of 514.5 nm, their spectra exhibit four series of photoluminescence lines, two of which (at λ = 521–523 and 538–564 nm) are emitted by Er³⁺ ions, “impurity” dopants, while the other two lines (at λ = 607–635 and 644–684 nm) are emitted by intrinsic centers. Under excitation by the radiation at a wavelength of 632.8 nm, only a series of bands at λ = 644–684 nm is emitted. In addition to these photoluminescence bands, neodymium-doped ceramics show photoluminescence bands of Nd³⁺ ions. We have shown that intrinsic luminescence centers, which occur in all the examined specimens, are capable of acting as acceptors with respect to neodymium ions excited to the upper laser level.     

ZnWO4∶Sm3+晶体光谱与上转换发光

采用Czochralski法生长出了ZnWO₄∶Sm³⁺单晶(Sm₂O₃=0.1wt%)，测量了晶体的吸收光谱.利用激光Raman谱仪在He-Ne激光器632.8nm波长激光激发下，观测到448，471，505，533nm的上转换锐线荧光，对其发光机理进行了探讨. 关键词：     

广东省石英质“台山玉”矿物谱学及其标型特征研究

石英质玉分布广泛,在我国十几个省区均有产出,是国内市场上重要的特色玉石品种,其使用历史悠久,是岭南先秦时期重要的玉石材料。石英质玉石的产地区分具有重要的宝石学和考古学意义。然而,由于石英质玉产地众多,外观、成分特征相似,尚缺乏有效的产地判别方法,其产地来源标型特征的研究仍然非常薄弱。"台山玉"是产于广东台山的一种石英质玉石,因其颜色质感酷似田黄而日益受到重视。该研究在常规的宝石学测试基础上,采用X射线粉末衍射(XRD)、傅里叶变换红外光谱(FTIR)、显微激光拉曼光谱(Raman)等分析方法,对6件具有代表性不同类型的台山玉的谱学特征及矿物组成进行了测试分析。实验结果显示,台山玉主要矿物为石英,次要矿物为地开石或高岭石;地开石、高岭石在台山玉中以其中一种为主,二者不共存;利用XRD-Rietveld法定量计算出台山玉中石英含量低于85 Wt%,高岭石族矿物含量介于17 Wt%~36 Wt%。台山玉的拉曼光谱缺失斜硅石的502 cm^-1特征峰,暗示了台山玉的主要矿物石英与玉髓、玛瑙类低温石英相比具有较高的结晶度;台山玉可分为地开石石英岩玉和高岭石石英岩玉两种类型,其中地开石型石英质台山玉红外光谱羟基振动区出现3 622, 3 653和3 703 cm^-1三个谱带,而拉曼光谱相应地出现3 622, 3 644和3 706 cm^-1三个谱带,二者均有谱带分裂明显,峰强向高频方向递减的特点,台山玉多为此类型;高岭石型台山玉红外光谱羟基振动区出现3 620, 3 652, 3 670和3 695 cm^-1四个谱带,而拉曼光谱出现3 620, 3 651, 3 670和3 687 cm^-1四个谱带,其中3 670 cm^-1带强度很弱,不易识别,该类型台山玉比例相对较少。台山玉中高有序度地开石、高岭石的出现指示其原岩中富Al质矿物经历了中温酸性热液交代蚀变作用,成矿条件与黄龙玉、金丝玉、霍山玉等石英岩玉存在差异。可以确定,地开石、高岭石是台山玉区别于其他产地石英岩玉的标型矿物。结果为台山玉的产地鉴定提供了科学依据,并为国内石英质玉的源区鉴定和古代石英质玉器的产地溯源提供了重要的参考。     

Study of Raman spectrum of uranium using a surface‐enhanced Raman scattering technique

Raman spectroscopic investigation on weak scatterers such as metals is a challenging scientific problem. Technologically important actinide metals such as uranium and plutonium have not been investigated using Raman spectroscopy possibly due to poor signal intensities. We report the first Raman spectrum of uranium metal using a surface‐enhanced Raman scattering‐like geometry where a thin gold overlayer is deposited on uranium. Raman spectra are detected from the pits and scratches on the sample and not from the smooth polished surface. The 514.5‐ and 785‐nm laser excitations resulted in the Raman spectra of uranium metal whereas 325‐nm excitation did not give rise to such spectra. Temperature dependence of the B_3g mode at 126 cm⁻¹ is also investigated. Copyright © 2011 John Wiley & Sons, Ltd.     

噻菌灵农药的表面增强拉曼光谱分析

利用表面增强拉曼光谱技术(SERS)分析噻菌灵农药的拉曼特征峰。采用微波法制备银溶胶表面增强基底,利用激光显微共焦拉曼光谱仪分别采集514.5和785 nm激发波长下的噻菌灵农药拉曼光谱,解析不同激发波长下的拉曼特征峰并进行比较。结果表明：不同激发波长下噻菌灵的拉曼峰强度和拉曼频移差异较大,514.5 nm激发波长下的782和1 012 cm-1最强,是C—H变形振动较强特征峰,而785 nm激发波长下的1 284,1 450和1 592 cm-1最强,是环振动和CN伸缩振动较强特征峰。对比分析各个激发波长下噻菌灵的SERS谱图,找到了噻菌灵农药的5个较强特征拉曼峰：782,1 012,1 284,1 450和1 592 cm-1。这些特征峰可作为食品及农产品中噻菌灵农药残留定性定量判别的依据。     

SERS activity of pulsed laser ablated silver thin films with controlled nanostructure

The surface‐enhanced Raman scattering (SERS) activity of silver thin films deposited by the pulsed laser ablation technique was investigated. The samples were grown in a controlled Ar atmosphere at pressures ranging between 10 and 70 Pa, and changing the number of laser pulses. Different surface morphologies, from isolated nearly spherical nanoparticles (NPs) to larger islands with smooth edges, were observed by means of scanning and transmission electron microscopies, as a function of the different deposition conditions adopted. SERS measurements were performed by soaking the samples in rhodamine 6G aqueous solutions over the concentration range between 1.0 × 10⁻⁴ and 5.0 × 10⁻⁸ M . Raman spectra were acquired using both the 632.8 and 514.5 nm excitation sources. The dependence of the SERS activity of the samples on the observed surface morphology is presented and discussed. The presence of the so called hot spots is envisaged. Copyright © 2011 John Wiley & Sons, Ltd.     

Raman spectroscopy study of in situ change in laser irradiated LiMn2O4

A spinel LiMn2O4 is investigated via Raman spectroscopy at 514.5-nm excitation and X-ray diffraction. The dependence of Raman spectra on the different irradiated laser powers is determined and found to be different from that at 632.8-nm excitation. Based on our extensive analysis, our experimental results can be attributed to the laser heating effect, which reduces the Mn4+ cation concentration in the local area. Consequently, the decrease in average Mn valence in the local area unavoidably induces the Jahn-Teller effect and local lattice distortion, which accounts for the evolution of the measured Raman spectra of spinel LiMn2O4.     

光纤共振和预共振喇曼光谱

在液芯光纤内产生共振和预共振喇曼效应,喇曼光谱强度可以大幅度提高,最高可达10⁹倍.本文介绍获得光纤(预)共振喇曼光谱的可行性、实验及实验结果.用远离吸收带的激光激发获得了α甲基吡啶预共振喇曼光谱.用小功率激光(0.8mW)、低浓度溶液(9.6×10¹²mol/L)还获得了β叶红素在CS₂中的共振喇曼光谱.     

The Non-Destructive Analysis of Some Ancient Jade Artifacts Unearthed from Henan Province by a Variety of Optical TechniquesSCIEI北大核心CSCD

A total of 14 pieces of ancient jade artifact unearthed from Henan Province were non-destructively analyzed by means of a portable X-ray fluorescence spectrometer (pXRF), laser Raman spectroscopy (portable and mobile) and optical coherence tomography (OCT) technology, comprehensively. The raw materials of ancient jade artifacts could be determined accurately through the combination of pXRF and portable Raman spectrometer in a short time. With the advantages of small size and easy-operation, these two instruments are suitable to in situ non-destructive analysis of ancient jade artifacts. The results of the pXRF shows that these ancient jade artifacts can be divided into 6 categories such as rich in Si Al K, rich in Ca, rich in Si Ca, rich in Si Mg, rich in Si, rich in Ca P. Their main phases have been successfully identified by the portable Raman spectrometer. In the lab, the mobile confocal laser Raman spectrometer, which help us find the Raman vibration peak of [OH] in the tremolite jade, is used to make up the disadvantages of the portable Raman spectrometer such as lower spectral resolution, lower accuracy and narrower measuring range. We can use the OCT to analyze the transparency, fiber fineness and inclusion etc. of the jade artifacts. The confocal laser Raman spectroscopy combined with OCT is used to analyze 2 containing inclusion of tremolite jade samples. OCT image can visually display the distribution characteristics of the inclusion in these 2 samples. Confocal laser Raman spectroscopy can accurately locate the sample surface of inclusion, then we can observe the micro morphology and analyze its phase. The results show that the black inclusion is graphite. This work is very significant to study the geographical origin of jade. Through the study we find, the use of OCRF, laser Raman spectroscopy (portable and mobile) and OCT can be achieved on the identification and analysis of cultural relic's phase composition and texture feature and meet the basic requirements of field archaeological work analysis.     

应用多种光学分析技术对一批河南出土古代玉器的无损分析

综合利用便携式X射线荧光光谱仪(pXRF)、激光Raman光谱仪(便携式和可移动式)以及光学相干层析成像(OCT)技术,对河南出土的14件东周玉器进行无损分析测试。pXRF和便携式微型Raman光谱仪(miniRaman)能够准确、快速的识别玉器的原材料和物相。且这两台仪器操作简单、体积小,可用于做现场原位、无损分析。根据pXRF检测结果,这批玉器按成分可分为富硅铝钾、富钙、富硅、富硅镁、富硅钙和富钙磷6大类。通过miniRaman快速地鉴定出这批样品的主要物相。在实验室里,使用可移动式共焦激光Raman光谱仪,可以弥补便携式微型Raman光谱仪在光谱分辨率、测量精度以及测量范围等方面的不足。利用共焦激光Raman光谱仪,检测到透闪石型玉器中[OH]根的Raman振动峰。OCT技术可以分析玉器材质的透明度、纤维粗细程度、包裹体分布等亚表面特征。将共焦激光Raman光谱仪与OCT分析仪有机结合分析了两件含包裹体的透闪石玉器样品,OCT图像可以直观地展示这两件样品中的包裹体分布特征,而共焦激光Raman光谱仪可以准确定位样品表面的包裹体,进行显微形貌观察及其物相分析,结果表明黑色的包裹体为石墨,这对玉器的产地溯源研究具有重要意义。通过研究发现,利用便携式X射线荧光光谱仪,激光Raman光谱仪和光学相干层析成像技术 ,可以实现对文物样品的物相组成和质地特征进行初步鉴别和分析,满足考古工作的现场基础分析要求。     

Investigation of some Chinese jade artifacts (5000 BC to 771 BC) by confocal laser micro‐Raman spectroscopy and other techniques

The study on material properties of ancient stone or jade artifacts is essential to trace the trade routes of raw materials, the tools used to making them, and moreover the social function of the artifacts. In present research, we focused on 23 intact samples that were made of versatile rocks. These samples dated from 5000 bc to 771 bc were unearthed from the Yellow River and Yangtze River basins in China. Based on the analytical results of confocal laser micro‐Raman spectroscopy, 14 minerals consisted of these rocks such as muscovite, antigorite, calcite, quartz, diopside, turquoise, corundum, and sillimanite were identified. The obtained scientific information about their primary material properties helps us to better understand their social functions and technologically related issues. Copyright © 2015 John Wiley & Sons, Ltd.     

R-3000便携式拉曼光谱仪在翡翠鉴定中的应用

使用R-3000便携式拉曼光谱仪,对缅甸原料、腾冲工艺的3个翡翠饰件和一个昆明古玩城所购翡翠挂件进行了无损鉴定。通过对检测样品拉曼光谱的比较研究,得出了有2个样品是由天然翡翠原料所制成;有一个样品含石蜡填充物;而有一个样品与天然翡翠无关,而是由石英岩（SiO2）为主要材料制成的,是假翡翠的结论。说明了R-3000便携式拉曼光谱仪,在玉石翡翠检测鉴定中是十分方便、快捷、准确的。     

He—Ne激光器粒子数反转径向分布光谱测量

用二维光学多道分析仪考察了He-Ne激光器在632.8nm激光振动和不振荡时氖能级3s_2和2p_k(k=1,2,……8,10)的侧光辐射,进行了Abel反演后,得到了3s_2和2p_k各能级粒子数和3s_2和2p_k间粒子数反转的径向分布,研究了此分布勺放电电流、632.8nm激光辐射强度间的关系,推算了在放电管中心3s_2和2p_k能级间受激辐射的激光增益。     

两种激发波长下蔬菜水果的拉曼光谱对比研究

本文通过改变不同的激光光源波长,测试分析了一系列蔬菜水果表面的拉曼谱。比较514.5nm和1064nm波长下的拉曼谱,发现514.5nm激发下许多蔬菜水果的拉曼谱均出现胡萝卜素的共振拉曼光谱,同时有很强的光荧光。更换成1064nm的近红外激光波长后,基本消除了光荧光和共振效应的影响,可用来测量蔬菜水果的有效成分,而514.5nm激发下只出现胡萝卜素的光谱,为区分蔬菜水果表面的外来物质,如农药,提供了很大的方便。     

HERAS: A helium jet to prevent damage on works of art in Raman experiments

Raman spectroscopy is often used for non‐destructive analysis of works of art, polymers and biological materials, but in some cases, the laser beam can cause damages on the surface being studied due to the deposited beam energy. When possible, such damage can be prevented by minimizing laser intensity or acquisition time, but this is usually available only on high sensitivity bench‐top spectrometers. Portable Raman spectrometers are commonly not so flexible and an alternative is needed to ensure the safe study of sensitive works of art and other fragile materials. A helium jet aimed directly at the laser spot may prevent this damage from occurring and, in some cases, helps improving the Raman spectra. We designed a simple system (HERAS, Helium Raman System) consisting of a pinhole collimator, coupled to a helium line and a gas mass flux control and tested it on pyroxylin, vermilion and ochre paint references and pigment samples, using a 785 nm portable Raman spectrometer at various laser powers. Experimental conditions slightly differ for each sample, but small burns on the surface were avoided in all cases and only some ablation was observed on the most sensitive materials. The use of this coupled system allows the non‐destructive application of Raman to a wider variety of materials, while the technique remains portable. This setup may be used in bench‐top apparatus as well. Copyright © 2013 John Wiley & Sons, Ltd.     

以PAA为模板制备SERS基底及对三聚氰胺的检测

采用热蒸镀的方法直接在多孔氧化铝(porous anodic alumina,PAA)模板上蒸镀几微米的银膜,然后在HCl溶液中溶解掉模板,得到表面具有纳米尺度规则结构的银膜作为表面增强拉曼散射(surface-en-hanced Raman spectra,SERS)基底,并在该基底上测量了吡啶溶液(0.01 mol.L-1)的增强拉曼光谱,发现平均增强因子大于105。与直接在载玻片上蒸镀的银膜相比,具有纳米尺度规则结构银膜的增强效果提高了30倍。改变激发光功率测量吡啶的拉曼光谱,和普通拉曼散射一样,增强拉曼光谱的峰值强度随激发光强度线性变化,并在该基底上测量了三聚氰胺的拉曼光谱,发现在1 mW的激发功率下对于三聚氰胺的检出限为2.5 mg.L-1。