Zeeman效应原子吸收分析中元素的吸收线分裂及其对灵敏度影响的研究——Ⅲ.稀土元素的吸收线

通过对Sc,Y和La等十六个稀土元素的60条谱线的Zeeman分裂谱图和在ZAAS(CPMPM方式)仪上灵敏度实验对比的研究,可得如下结论:(1)在10kG横向恒磁场偏振分离调制方式里,所研究的60余条谱线中,只有4条线的灵敏度下降到原来的1/3以下,大约有45条线的A_r>0.50.可以认为,在ZAAS仪上,从分析应用角度来看,这些元素的主要吸收线灵敏度受Zeeman分裂影响较小,与NAAS相近。因此此仪对稀土元素的通同性是肯定的。(2)鉴于Sm,Nd,Eu,Ce四种元素的主吸收线在ZAAS仪上灵敏度下降较多,建议以Nd 4634.34A,Sm 4841.70A,Eu 4627.22A及Ce 5669.96A四线为这类仪上的主分析线。(3)对Sm 4296.74和4841.70A,Nd4634.34A,Ce5669.96和5201.30A,Dy4186.81A及Y4128.31A为典型代表的31条谱线能级进行了讨论。依据文献J和g_(ob)值绘出了较合理的Zeeman谱图。     

Zeeman原子吸收光谱分析法中谱线轮廓的研究I.原子发射谱线.原子吸收谱线和Zeeman原子吸收谱线轮廓间重叠关系图的建立

详细报道用理论计算和绘制的37个元素分析线的发射轮廓. 吸收线轮廓和Zeeman分裂后的吸收线轮廓, 并建立了在原子吸收光谱法中三者轮廓间的重叠关系     

Zeeman原子吸收光谱分析法中谱线轮廓的研究I.原子发射谱线.原子吸收谱线和Zeeman原子吸收谱线轮廓间重叠关系图的建立

详细报道用理论计算和绘制的37个元素分析线的发射轮廓. 吸收线轮廓和Zeeman分裂后的吸收线轮廓, 并建立了在原子吸收光谱法中三者轮廓间的重叠关系     

Zeeman原子吸收光谱分析法中谱线轮廓的研究 Ⅰ.原子发射谱线、原子吸收谱线和Zeeman原子吸收谱线轮廓间重叠关系图的建立

详细报道用理论计算和绘制的37个元素分析线的发射线轮廓、吸收线轮廓和Zeeman分裂后的吸收线轮廓,并建立了在原子吸收光谱法中三者轮廓间的重叠关系图.     

Zeeman效应原子吸收分析中元素的吸收线分裂及其对灵敏度影响的研究Ⅰ.钪、钇、稀土除外的Ⅰ～Ⅷ族元素的吸收线

按照原子光谱理论,本文绘出了Ⅰ～Ⅷ族中38个元素约200余条吸收线的Zeeman分裂谱图.并对这些线在Zeeman原子吸收仪和普通原子吸收仪上进行了灵敏度的实验比较.从实验数据和谱图的研究中,可以有如下结论:(1)Ⅱ,Ⅳ,Ⅷ族元素的主要和大部分吸收线的灵敏度受Zeeman分裂影响较少.多数相对吸光度A_r=0.7～1.0.其中不仅有正常三线分裂的跃迁,也包括π成分分裂为2～10个精细组分,而π和σ±成分重叠极少的反常分裂跃迁.Ⅰ,Ⅲ,Ⅴ,Ⅵ,Ⅶ族元素的主要吸收线呈现π成分分裂为间距较大的2～6组分的反常分裂.其灵敏度有约50%左右的下降,A_r=0.3～0.6.然而对高灵敏度石墨炉分析而言,这种损失无足轻重.上述两类包括了所研究谱线中绝大多数谱线.因此可以说在横向恒磁场偏振分离调制方式的Zeeman原子吸收仪上绝大多数吸收线的灵敏度与普通原子吸收仪相近或同量级;(2)只有Ⅰ族次灵敏线和其它元素个别不常用的谱线呈现π和σ±成分有较大重叠的反常分裂,灵敏度有明显的损失,一般A_r<0.2.然而,仅有7条线的A_r值小于0.1;(3)Cu,In,Sn,Bi,Li及Au受精细或超精细结构作用,Zeeman分裂对灵敏度的影响可能变得复杂.建议分析应用时,以In3256.09Å代替In3039.36Å为主分析线.     

Zeeman效应原子吸收分析中元素的吸收线分裂及其对灵敏度影响的研究Ⅱ.精细和超精细结构的作用

应用Voigt函数近似计算公式和光谱线叠加原理,本文描绘了Cu3247.54Å,Bi3067.70Å,Li6707.84和6707.99A双线,Au2427.95Å以及Ag3280.68Å在Zeeman效应原子吸收分析(简称ZAAS)和普通原子吸收分析(简称NAAS)中的吸收线和发射线轮廓.用作图面积积分的方法,估算了ZAAS对NAAS的相对吸光度.计算值与实验值比较相符.从谱线轮廓图和相对吸光度的估算得知:Δν_hfs与Δν_σ-⁺相当,则K_π可能为K_σ-⁺所抵消,灵敏度下降,如Cu3247.54Å和Bi3067.70Å;精细结构双线间距Δν_f与Δν_σ-⁺相当,则K_π也将为K_σ-⁺抵消,灵敏度下降,如Li双线;在一定的磁场强度下,某些谱线所具有的超精细结构间距,却可以使发射线轮廓内K_π得到加强,由Zeeman分裂而导致的灵敏度损失将减少,如Au2427.95A;Lorentz位移和谱线全变宽的大小,都可能造成Zeeman分裂对灵敏度影响大小的变化.     

Zeeman效应原子吸收分析法中元素的吸收线分裂及其对灵敏度影响的研究

按照原子光谱理论,本工作绘出了Ⅰ—Ⅷ族中38个元素(稀土不在内)210余条吸收线的Zecman分裂谱图(全文以后发表)。根据L'vov原子化理论,不同类型的石墨炉峰值灵敏度θ与其石墨管截面积S间的关系为     

Zeeman效应AAS中元素的吸收线分裂行为的研究

本课题包括三方面内容: 1.绘制了周期系Ⅰ-Ⅷ族元素吸收线的Zeeman分裂谱图,以往文献只见过51条线15幅图,稀土元素zeeman谱图是空白。本工作列出包括稀土元素在内的250条线97幅Zeeman图。结合谱图对灵敏度的影响的统计趋势的实验研究,第一次给商品ZAAS使用者提供系统、完整有半定量概念的Zeeman谱图。     

用次灵敏线原子吸收法测定铅锌矿石中铅锌

微量铅锌的原子吸收分析报道很多.矿石中高含量铅锌的测定,通常采用络合滴定法,但干扰较多、流程较长.高含量铅锌的原子吸收直接测定,则所见报道不多.本文研究了利用次灵敏线测定矿石中高含量铅锌.样品经酸溶并定容到一定体积后,可不经稀释用原子吸收仪直接进行铅、锌测定.方法简便、快速.检测结果与按国家标准分析方法结果比较,其准确度、精密度均符合要求.1试验部分1.1仪器与试剂GGX-1型原子吸收分光光度计铅、锌标准液:2.000mg·ml~(-1),2%硝酸(体积分数,下同).其他试剂均为分析纯1.2仪器工作条件选择次灵敏线铅368.4nm,锌307.6nm,空气-乙炔火焰比例根据仪器情况调整.因铅、锌灵敏度及线性范围受火焰影响,故测量过程中要求火焰状态     

邻近非共振线背景校正-火焰原子吸收法测定酱油中的铅

利用火焰原子吸收光谱法测定高盐样品中的铅含量[1]时,由于分子吸收和光散射等背景吸收原因,测定结果会偏高,用氘灯无法理想地校正;塞曼效应虽然可以校正,但仪器成本较高,一般基层单位难以承受。邻近非共振线背景校正技术[2,3]虽然早在20世纪60年代就有文献报道,但具体操作方法     

Simple mode of zeeman splitting of absorption lines in atomic absorption spectrometry

Simple equipment is described for exploiting the normal Zeeman splitting of atomic absorption lines in external alternating magnetic fields of various geometry which is suitable for flameless and flame techniques. High-level continuous or background absorption can be eliminated in this way. This is demonstrated for the determination of traces of copper and molybdenum with a carbon rod (Varian CRA 90).     

Fraunhofer-type absorption line splitting and polarization in confocal double-pulse laser induced plasma

Strong line splitting and polarization are observed in Fraunhofer-type absorption lines in Pb, Sn, Si, Cd, In, and Zn in confocal double-pulse laser induced plasma (DP-LIP) experiments. This effect is detectable using medium laser power densities: (~ 1–2) × 10¹³ W/m² for the first laser pulse and 1 × 10¹⁴ W/m² for the second laser pulse. Polarization and splitting effects exist only during the second laser pulse (~ 7 ns). Absorption line polarization and splitting phenomena may be explained by a high overall magnetic field and motional Stark effect caused by the second laser pulse inside the laser plasma created by the first pulse.     

Dimensional effects on the LO-TO splitting in CF4: first-principles and infrared absorption studies

The development of longitudinal optical-transverse optical (LO-TO) modes in CF(4) has been studied experimentally and theoretically as a function of dimensionality. Infrared absorption experiments for CF(4) adsorbed on single-walled carbon nanotubes indicate a lack of LO-TO splitting at low coverage and a gradual appearance of LO-TO modes as the coverage of CF(4) on the nanotubes is increased. We have performed density functional perturbation theory calculations for the vibrational frequencies, IR absorption spectra, and phonon density of states for CF(4) in one, two, and three dimensions. The calculations demonstrate that LO-TO splitting in 1D is qualitatively different from that computed for 2D or the bulk. The magnitude of the splitting in 1D is about one-half that computed for the bulk, and the LO mode is very weakly blue-shifted in 1D. We predict that the phonon density of states changes dramatically as the dimensionality of the crystal is changed. This prediction can be tested experimentally via inelastic neutron scattering. We conclude that LO-TO splitting can be used as a probe to identify 1D states of matter.     

Temperature dependences of mechanisms responsible for the water-vapor continuum absorption. I. Far wings of allowed lines

It is well known that the water-vapor continuum plays an important role in the radiative balance in the Earth's atmosphere. This was first discovered by Elsasser almost 70 years ago, and since that time there has been a large body of work, both experimental and theoretical, on this topic. It has been experimentally shown that for ambient atmospheric conditions, the continuum absorption scales quadratically with the H(2)O number density and has a strong, negative temperature dependence (T dependence). Over the years, there have been three different theoretical mechanisms postulated: Far wings of allowed transitions, water dimers, and collision-induced absorption. Despite the improvements in experimental data, at present there is no consensus on which mechanism is primarily responsible for the absorption. The first mechanism proposed was the accumulation of the far-wing absorption of the strong allowed transitions. Later, absorption by water dimers was proposed and this mechanism provides a qualitative explanation for the strong, negative T dependence. Recently, some atmospheric modelers have proposed that collision-induced absorption is one of the major contributors. However, based on improvements in the theoretical calculation of accurate far-wing line shapes, ab initio dimer calculations, and theoretical collision-induced absorptions, it is now generally accepted that the dominant mechanism for the absorption in the infrared (IR) windows is that due to the far wings. Whether this is true for other spectral regions is not presently established. Although all these three mechanisms have a negative T dependence, their T dependences will be characterized by individual features. To analyze the characteristics of the latter will enable one to assess their roles with more certainty. In this paper, we present a detailed study of the T dependence of the far-wing absorption mechanism. We will then compare our theoretical calculations with the most recent and accurate experimental data in the IR windows. The results of our calculations are found to agree very well with measurements in the 800-1200 cm(-1) region. We conclude from this work that the T dependence in the IR window region predicted by the far-wing theory is negative and moderately strong. Its pattern is not simple and it could vary significantly as the frequency of interest varies.     

Direct absorption measurement of the spin—orbit splitting of the ground state in atomic fluorine

We have measured the three hyperfine components of the spin—orbit split (²P_{$\text{3}\text{2}$} → ²P_{$\text{1}\text{2}$}) ground state in atomic fluorine by diode laser absorption spectroscopy. The measurement improves the accuracy of the two lines previously reported (404.175 and 403.969 cm^?1), with the third line at 404.210 cm^?1. This confirms the spacing of the hyperfine components measured by EPR, and establishes diode laser absorption as a viable technique for determining F-atom concentrations.     

Theory of white lines in the x-ray absorption spectra of lanthanide complexes

Self-consistent multiple scattered wave formation was used to calculate the theoretical L-absorption edges of hydrated and unhydrated erbium trichloride in both bound state and continuum regions, in order to investigate the white line behavior. The white line was found to correspond to a transition to a d-like bound state lying just below the continuum threshold.     

Interferences in inverse zeeman-corrected atomic absorption spectrometry caused by zeeman splitting of molecules

Orthophosphoric acid was vaporized in the graphite furnace of an inverse Zeeman-corrected atomic absorption spectrometer and the performance of the background corrector system was studied at some analyte lines in the wavelength region where the species PO is known to have strong band systems. The investigation revealed cases of both over- and under-compensation probably caused by Zeeman splitting of PO rotational lines.     

Selective two-quantum laser excitation of molecules with overlapping absorption lines

A method of two-quantum excitation of molecules at Doppler-broadened transitions in a standing-wave radiation field is considered. It is shown that it is possible to increase the excitation selectivity of molecules with overlapping absorption lines when using spectra of two-photon absorption. Estimations of two-quantum transition probabilities for molecular gases are given.