Journal of research of the National Bureau of Standards. Section A, Physics and chemistry最新文献

英文中文

Ion-Neutralization Spectroscopy. 离子中和光谱学。

Journal of research of the National Bureau of Standards. Section A, Physics and chemistry

Pub Date : 1970-05-01 DOI: 10.1116/1.1315830

H. D. Hagstrum

The ion-neutralization spectroscopy (INS) is discussed in comparison with other spectroscopies of solids. It is shown that INS probes the local density of states of the solid at or just outside the solid surface. It is believed that this accounts for the clear-cut differences between INS results and those of other spectroscopies. Because of its unique specificity to the surface region INS is particularly useful in studying the surface electronic structures of atomically clean surfaces and of surfaces having ordered arrays of known atoms adsorbed upon them. In the latter case INS determines a portion of the molecular orbital spectrum of surface molecules formed from the adsorbed foreign atom and surface atoms of the bulk crystal. Such spectra provide information on local bonding symmetry and structure and electrical charging within the surface molecule which is as yet unavailable by any other method. INS is the first attempt to base a spectroscopy of electronic states on a two-electron process. More recent work on experimental and mathematical problems which such a spectroscopy entails are also briefly mentioned in this paper.

讨论了离子中和光谱(INS)与其他固体光谱的比较。结果表明，INS可以探测固体表面或表面外的局部态密度。相信这是INS结果与其他光谱结果明显不同的原因。由于其对表面区域的独特特异性，INS在研究原子清洁表面和已知原子有序排列在其上的表面的表面电子结构方面特别有用。在后一种情况下，INS确定由吸附的外来原子和本体晶体的表面原子形成的表面分子的分子轨道谱的一部分。这种光谱提供了局部键对称、结构和表面分子内电荷的信息，这是迄今为止任何其他方法都无法获得的。INS是基于双电子过程的电子态光谱的第一次尝试。本文还简要地提到了有关这种光谱学所涉及的实验和数学问题的最新工作。

引用次数: 9

Periodic Acid, a Novel Oxidant of Polycyclic, Aromatic Hydrocarbons. 多环芳烃的新型氧化剂周期酸。

Journal of research of the National Bureau of Standards. Section A, Physics and chemistry

Pub Date : 1968-07-01 DOI: 10.1039/C19670001087

A. Fatiadi

Certain polycyclic, aromatic hydrocarbons can be oxidized with periodic acid in aprotic solvents containing a small proportion of water. A unique, two-fold character of response to periodic acid by these hydrocarbons has been found: (1) production of a coupling reaction through a radical intermediate [conversion of pyrene into 1,1'-bipyrene, and fluorene into 1,2-bis(2,2'-biphenylylene)ethylene] or (2) conversion into quinones by a two-equivalent oxidation mechanism that does not involve a radical intermediate [acenaphthene, anthracene, anthrone, benz[a]anthracene, naphthacene, naphthalene, and phenanthrene]. Little or no reaction was observed when oxidation was attempted with sodium metaperiodate instead of periodic acid. Electron-spin resonance revealed no radical intermediate in the oxidation of malonic acid with either periodic acid or sodium periodate.

在含少量水的非质子溶剂中，某些多环芳烃可以与周期酸氧化。这些碳氢化合物对周期性酸的反应具有独特的双重特征:(1)通过自由基中间体[将芘转化为1,1'-联苯，将芴转化为1,2-二(2,2'-联苯)乙烯]产生偶联反应，或(2)通过双等效氧化机制转化为醌，而不涉及自由基中间体[苊、蒽、蒽酮、苯[A]蒽、萘、萘和菲]。当尝试用偏碘酸钠代替周期酸氧化时，观察到很少或没有反应。电子自旋共振显示，在与周期酸或高碘酸钠氧化丙二酸过程中，均未发现自由基中间体。

引用次数: 4

Buffer Solutions of Potassium Dihydrogen Phosphate and Sodium Succinate at 25 °C. 25 °C 下的磷酸二氢钾和琥珀酸钠缓冲溶液。

Journal of research of the National Bureau of Standards. Section A, Physics and chemistry

Pub Date : 1963-11-01 Epub Date: 1963-12-01 DOI: 10.6028/jres.067A.055

Maya Paabo, Roger G Bates, Robert A Robinson

A buffer mixture consisting of equal molalities (m) of potassium dihydrogen phosphate and sodium succinate is proposed as a useful reference point in the study of acid-base equilibria, bridging the present gap between pH 5.5 and pH 6.8. The p(a_H γ _Cl) at 25 °C has been determined by electromotive-force measurements for five buffer solutions in which m varied from 0.005 to 0.025. The conventional pa _H of each solution has been derived and found to be in good agreement with that calculated from existing data for the two equilibria concerned. The pa _H varies from 6.251 at m=0.005 to 6.109 at m= 0.025. The buffer mixture has been used successfully for the determination of the dissociation constants of 2-nitro-4-chlorophenol and 2,6-dichlorophenol.

我们提出了一种由等摩尔（m）磷酸二氢钾和琥珀酸钠组成的缓冲混合物，作为研究酸碱平衡的有用参考点，弥补了目前 pH 5.5 和 pH 6.8 之间的差距。在 25 °C 时的 p(aH γ Cl) 是通过测量五种缓冲溶液的电动力测定的，其中 m 在 0.005 至 0.025 之间变化。得出了每种溶液的常规 pa H，并发现其与根据现有数据计算出的两种相关平衡的 pa H 非常一致。pa H 从 m=0.005 时的 6.251 到 m=0.025 时的 6.109 不等。该缓冲混合物已成功用于测定 2-硝基-4-氯苯酚和 2,6-二氯苯酚的解离常数。

引用次数: 0

Tritium-Labeled Compounds IX. Determination of Isotope Effects in Reactions Yielding Water-t from Nonvolatile Reactants. Oxidation of Aldoses-1-t With Iodine. 氚标记化合物 IX.测定非挥发性反应物在生成水-t 反应中的同位素效应。碘氧化醛-1-t。

Journal of research of the National Bureau of Standards. Section A, Physics and chemistry

Pub Date : 1963-11-01 Epub Date: 1963-12-01 DOI: 10.6028/jres.067A.054

Horace S Isbell, Lorna T Sniegoski

A convenient method is presented for estimating isotope effects in reactions which yield water-t. The water-t is separated by freeze-drying, and k*/k is calculated from the extent of the reaction and the ratio of the radioactivity of the water-t to that of the initial reactant. Application of the method to the oxidation of aldoses-1-t at 25 °C with iodine in alkaline solution gives values for k*/k ranging from 0.12 to 0.17, with an average of 0.14. There are no significant differences in the values of k*/k obtained for aldoses differing in configuration, or for pentoses and hexoses. The isotope effect corresponds to a ratio of one to seven for the respective rates of reaction of the labeled and unlabeled molecules.

本文提出了一种简便的方法，用于估算产生水-t 的反应中的同位素效应。通过冷冻干燥分离出水-t，然后根据反应程度和水-t 的放射性与初始反应物的放射性之比计算出 k*/k。将该方法应用于在 25 °C 下用碘在碱性溶液中氧化醛糖-1-t，得出的 k*/k 值在 0.12 到 0.17 之间，平均值为 0.14。不同构型的醛糖、戊糖和己糖的 k*/k 值没有明显差异。同位素效应相当于已标记和未标记分子各自反应速率的一比七。

引用次数: 0

Recalibration of the NBS Glass Standards of Spectral Transmittance1 NBS玻璃光谱透过率标准的再标定

Journal of research of the National Bureau of Standards. Section A, Physics and chemistry

Pub Date : 1963-11-01 DOI: 10.6028/jres.067A.056

H. J. Keegan, J. C. Schleter, M. Belknap

In 1934, Gibson, Walker, and Brown developed sets of four colored glass filters to serve as working standards of spectral transmittance for checking the reliability of spectrophotometers. Several sets of these glasses were measured carefully and reserved and designated as future reference standards. Duplicate standards evaluated by comparison with the reference standards are available by purchase to the public. The current set of reference standards was established in the years 1945 to 1947, and one of these reference standards (selenium-red) was recalibrated in 1952. This paper reports a recalibration, made in 1961 and 1962, of all four glasses (selenium-red, carbon-yellow, copper-green, cobalt-blue) on three spectrophotometers (Cary 14, Beckman DU, König-Martens). Except for the cobalt-blue standard, the values of spectral transmittance found differ from those previously assigned by amounts differing at some wavelengths by as much as or slightly more than the uncertainties estimated for the present values, though not by amounts exceeding the combined uncertainties of the present and previous determinations. The indicated changes for these three standards are fairly regular, however, and support the view that the selenium-red and carbon-yellow standards are changing chiefly by formation of a reflectance-reducing film on the surfaces. The indicated rate of upward drift is slow, and suggests that it takes about 10 years for the drift to exceed the assigned uncertainity.

1934年，Gibson, Walker和Brown开发了一套四种彩色玻璃滤光片，作为检查分光光度计可靠性的光谱透射率的工作标准。有几套这样的玻璃杯被仔细地测量过，并保留下来作为将来的参考标准。通过与参考标准比较评估的重复标准可向公众购买。目前的一套参考标准是在1945年至1947年建立的，其中一个参考标准(硒红)于1952年重新校准。本文报告了1961年和1962年在三个分光光度计(Cary 14, Beckman DU, König-Martens)上对所有四种玻璃(硒红，碳黄，铜绿，钴蓝)进行的重新校准。除了钴蓝标准外，所发现的光谱透过率值与先前的值不同，在某些波长上的差异与当前值估计的不确定度相差相同或略大，但不超过当前和以前测定的不确定度总和。然而，这三种标准的变化是相当有规律的，这支持了硒红和碳黄标准的变化主要是由于表面上形成了一层减少反射的薄膜。所指示的向上漂移的速率是缓慢的，并且表明漂移需要大约10年的时间才能超过指定的不确定度。

{"title":"Recalibration of the NBS Glass Standards of Spectral Transmittance1","authors":"H. J. Keegan, J. C. Schleter, M. Belknap","doi":"10.6028/jres.067A.056","DOIUrl":"https://doi.org/10.6028/jres.067A.056","url":null,"abstract":"In 1934, Gibson, Walker, and Brown developed sets of four colored glass filters to serve as working standards of spectral transmittance for checking the reliability of spectrophotometers. Several sets of these glasses were measured carefully and reserved and designated as future reference standards. Duplicate standards evaluated by comparison with the reference standards are available by purchase to the public. The current set of reference standards was established in the years 1945 to 1947, and one of these reference standards (selenium-red) was recalibrated in 1952. This paper reports a recalibration, made in 1961 and 1962, of all four glasses (selenium-red, carbon-yellow, copper-green, cobalt-blue) on three spectrophotometers (Cary 14, Beckman DU, König-Martens). Except for the cobalt-blue standard, the values of spectral transmittance found differ from those previously assigned by amounts differing at some wavelengths by as much as or slightly more than the uncertainties estimated for the present values, though not by amounts exceeding the combined uncertainties of the present and previous determinations. The indicated changes for these three standards are fairly regular, however, and support the view that the selenium-red and carbon-yellow standards are changing chiefly by formation of a reflectance-reducing film on the surfaces. The indicated rate of upward drift is slow, and suggests that it takes about 10 years for the drift to exceed the assigned uncertainity.","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1963-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84391777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Adsorption, Desorption, Resorption 吸附、解吸、再吸收

Journal of research of the National Bureau of Standards. Section A, Physics and chemistry

Pub Date : 1963-11-01 DOI: 10.6028/jres.067A.061

W. V. Loebenstein

The complete characterization of batch adsorption from solution, desorption, and related phenomena have been interpreted in the light of a general equation. The forward and reverse adsorption-rate constants and the adsorptive capacity comprise the only parameters. Where adsorption alone is of importance and the desorption-rate constant can be neglected, a simplified form of the theory results in a special equation which may suffice for most adsorption purposes. In either case, the characteristic parameters are determinable from the data and serve as criteria for comparing similar systems. The theory has been confirmed by the data of various investigators taken from the literature. The parameters derived from column adsorption are in agreement with the corresponding batch-derived parameters. The limitations as well as the capabilities of the theory are presented; but even where deviations from the assumed model exist, the results are useful.

从溶液中批量吸附，解吸和相关现象的完整表征已经解释在一个一般方程的光。正向和反向吸附速率常数和吸附容量是唯一的参数。当吸附本身是重要的，而解吸速率常数可以忽略不计时，该理论的简化形式可以得到一个特殊的方程，它可以满足大多数吸附目的。在任何一种情况下，特征参数都可以从数据中确定，并作为比较类似系统的标准。这一理论已被各种研究人员从文献中获得的数据所证实。柱吸附得到的参数与相应的批量导出参数一致。指出了该理论的局限性和能力;但是，即使存在与假设模型的偏差，其结果也是有用的。

引用次数: 6

Color Phenomena in Polymer Fracture. 聚合物断裂中的颜色现象

Journal of research of the National Bureau of Standards. Section A, Physics and chemistry

Pub Date : 1963-11-01 Epub Date: 1963-12-01 DOI: 10.6028/jres.067A.062

Sanford B Newman, Irvin Wolock

Thin layers derived from the matrix are produced in the fracture plane of some polymers prior to ultimate failure. A certain amount of the evidence would indicate that these layers consist of an oriented array of molecules. Fracture isolates these molecular segments in a thin film with physical properties differing from that of the matrix in which they originated. These films produce interference phenomena which in some cases are useful in elucidating structure and origin.

某些聚合物在最终失效之前，会在断裂面上产生来自基体的薄层。大量证据表明，这些薄层由定向排列的分子组成。断裂将这些分子片段隔离在一层薄膜中，薄膜的物理性质不同于基体的物理性质。这些薄膜会产生干涉现象，在某些情况下有助于阐明结构和起源。

引用次数: 0

A Study of the Gas-Stabilized Arc as an Emission Source for the Measurement of Oscillator Strengths. Determination of Some Relative gf-Values for Fe I* 气体稳定电弧作为发射源测量振荡器强度的研究。铁中一些相对gf值的测定

Journal of research of the National Bureau of Standards. Section A, Physics and chemistry

Pub Date : 1963-11-01 DOI: 10.6028/jres.067A.053

M. Margoshes, B. F. Scribner

A study has been made of the application of the gas-stabilized arc source to the determination of oscillator strengths in atomic spectra. In this source, a solution of salts of one or more elements may be injected and the elements excited directly in an arc plasma with steady emission of spectral intensities. The source can be taken to be characterized by local thermal equilibrium, but with a large radial temperature gradient. An experiment indicates that when two elements are introduced into the arc in a solution, the relative concentrations of the elements in the discharge are the same as in the solution within the probable experimental error. This experiment indicates one way that the arc may be used for the determination of absolute oscillator strengths. New measurements are reported of the gf-values of 105 lines of Fe I between 2900 and 4150 Å, and the new values are compared with the results of earlier measurements.

研究了气体稳定电弧源在原子光谱中振荡强度测定中的应用。在这种源中，可以注入一种或多种元素的盐溶液，并在具有稳定光谱强度发射的电弧等离子体中直接激发元素。热源具有局部热平衡的特征，但径向温度梯度较大。实验表明，当两种元素在溶液中的电弧中引入时，在可能的实验误差范围内，放电中元素的相对浓度与溶液中元素的相对浓度相同。这一实验表明，电弧可用于确定绝对振荡器强度的一种方法。报道了在2900 ~ 4150 Å之间105行Fe - I的gf值的新测量结果，并将新值与先前的测量结果进行了比较。

引用次数: 11

Matrices of Spin-Orbit Interaction in the Electron Configurations np2 n′ p and np4 n′ p 电子构型np2 n ' p和np4 n ' p中自旋-轨道相互作用矩阵

Journal of research of the National Bureau of Standards. Section A, Physics and chemistry

Pub Date : 1963-11-01 DOI: 10.6028/jres.067A.052

J. Tech

The matrices of spin-orbit interaction in the p2 p and p4 p electron configurations have been calculated. The matrices have been checked by showing that their eigenvalues, calculated by use of an IBM 7090, agree with the correct eigenvalues known from the theory of jj-coupling. For the sake of completeness, the matrices of electrostatic interaction for these configurations are also given.

计算了p2p和p4p电子组态的自旋轨道相互作用矩阵。用IBM 7090计算的矩阵的特征值与j-耦合理论中已知的正确特征值一致，从而对矩阵进行了检验。为了完整起见，还给出了这些构型的静电相互作用矩阵。

引用次数: 7

Absolute Configuration and Chemical Topology 绝对构型和化学拓扑

Journal of research of the National Bureau of Standards. Section A, Physics and chemistry

Pub Date : 1963-11-01 DOI: 10.6028/jres.067A.058

S. J. Tauber

The stereochemistry of catenanes, knotted molecules, and Borromean rings is discussed. An augmentation of the Cahn-Ingold-Prelog convention for designating absolute configuration is proposed. A convention is proposed for designating the absolute configuration of knotted molecules. A suggestion is made concerning the citing of the absolute configuration of molecularly dissymmetric diastereomers.

讨论了链烷、结分子和博罗米安环的立体化学。提出了对Cahn-Ingold-Prelog约定的一种扩充，用于指定绝对构型。提出了一种确定打结分子绝对构型的惯例。对分子不对称非对映体绝对构型的引用提出了建议。

引用次数: 16

首页上一页

下一页尾页

类型

全部化学•材料生命科学医学物理工程技术环境•农林材料科学地球科学法学管理学化学环境科学与生态学计算机科学教育学经济学农林科学人文科学生物学数学物理与天体物理心理学综合性期刊其他工业工程理学历史学农学文学信息工程

数据库

全部 ACS Publications Elsevier ieeexplore Springer The Royal Society of Chemistry Wiley

期刊

Journal of research of the National Bureau of Standards. Section A, Physics and chemistry

全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.

﹀