The Spectrum of Doubly Ionized Tungsten (W III)

The spectrum of doubly ionized tungsten (W III) was produced in a sliding-spark discharge and recorded photographically on the NIST 10.7-m normal-incidence vacuum spectrograph in the 600–2680 Å spectral region. The analysis has led to the establishment of 71 levels of the interacting 5d⁴, 5d³ 6s and 5d² 6s² even configurations and 164 levels of the interacting 5d³ 6p and 5d² 6s 6p odd ones. A total of 2636 lines have been classified as transitions between the 235 experimentally determined levels. Comparison between the observed levels and those calculated from matrix diagonalizations with least-squares fitted parameters shows an rms deviation of ±87 cm⁻¹ for the even configurations and ±450 cm⁻¹ for the odd ones.     

Analysis of the Spectrum of Neutral Atomic Bromine (Br I)

The spectrum of the neutral bromine atom, Br I, has been newly investigated by using electrodeless discharge tubes as light sources. The observations have led to a list of wavelengths and estimated intensities for 1253 spectral lines in the range 1067 to 24100 Å. The number of known energy levels has been increased to 123 even and 128 odd levels, as compared with the 27 even and 33 odd levels previously known. All predicted energy levels of the 4s²4p⁴ns, up, nd, nf electron configurations from 0 to ~93250 K have been discovered. The observations in the vacuum ultraviolet establish that the positions of all the levels lying above those of the ground configuration as given in the compilation Atomic Energy Levels, Vol. II (1952) should be increased by 6.7 K. All but 26 faint lines of Br I have been classified. A total of 67 levels has been ascribed to the 4s² 4p* nf configurations. It is demonstrated that the nf configurations exhibit almost pure pair coupling. The very regular (³P₂)nf[5]°_11/2 series yields for the principal ionization energy of Br I the value 95284.8 K.     

Analysis of the Spectrum of Doubly Ionized Molybdenum (Mo III)

The spectrum of doubly ionized molybdenum (Mo III) was produced in a sliding spark discharge and recorded photographically on the NIST 10.7-m normal incidence spectrograph in the 800-3250 Å spectral region. The analysis has led to the establishment of 76 levels of the interacting 4d⁴, 4d³ 5s and 4d² 5s² even configurations, 73 levels of the interacting 4d³ 5d and 4d³ 6s even configurations, and 181 levels of the interacting 4d³ 5p and 4d² 5s5p odd configurations. Approximately 3100 lines have been classified as transitions between these experimentally determined levels. Comparison between the observed levels and those calculated from matrix diagonalizations with least-squares fitted parameters shows standard deviations of 44, 33, and 183 cm⁻¹, respectively, for the levels of the three sets of configurations.     

Spectrum of Scattered Light by an Ionized Two-level Atom

Abstract

The spectrum of scattered light by an ionized two-level atom is investigated. The ionization is considered as a damping out of the ordinary two-level system and its effect on the spectrum is extracted. Because of the ionization damping, the central peak in the spectrum changes significantly according to the parameters involved. For a large ionization damping, a central dip is observed; for a small ionization damping, an additional sharp peak appears on top of the central peak.     

Analysis of the First Spectrum of Ruthenium (Ru I)

The analysis of the first spectrum of ruthenium has been extended with the aid of digital computers. A total of 105 even and 206 odd levels are listed with observed Landé g-factors for 54 even and 148 odd levels. A complete list of approximately 3,400 classified lines in the range 2013 to 11484 A is presented. The ionization limit calculated from a two member series is 59410 cm⁻¹ or 7.364 v.     

Description and Analysis of the First Spectrum of Iodine

An extensive survey of the spectra of iodine has led to a list of more than 900 lines emitted by neutral atoms in the region from 23070 A in the infrared to 1195 A in the extreme ultraviolet. Wavelengths between 12304 A and 2061 A were derived from measurements of spectrograms obtained with gratings of high dispersion. Wavelengths of lines outside these limits are the computed values for lines observed on photometric tracings of the infrared, inaccessible to photography, and in the ultraviolet with a vacuum-grating spectrograph. For many of the lines Zeeman patterns were obtained in a magnetic field of about 37,000 oersteds. With these data many of the lines have been classified as combinations between odd levels from the electron configurations 5s² 5p⁴ np and 5s² 5p⁴ nf, and even levels from the configurations 5s² 5p⁴ ns and 5s² 5p⁴ nd. Among these levels several sets have been recognized as forming Rydberg sequences that are in close agreement in placing the ground state 5p⁵ 2P1½o of I i at 84,340 cm⁻¹ below the ground state 5p^{4 3}P₂ of I ii. This gives 10.45 electron-volts for the ionization potential of the neutral iodine atom. A strong infrared line at 13148.8 A is explained as a magnetic dipole transition between the levels of the ground term 5p^{5 2}P°.     

Supplementary Zeeman Data for the First Spectrum of Ruthenium (Ru I)

Zeeman data are listed for 207 lines of Ru I between 2400 and 5400 A, all of which have been classified. The spectrograms were made at the Massachusetts Institute of Technology and were analyzed there and at the National Bureau of Standards.Harrison and McNally² published Zeeman data for 450 lines of the first spectrum of ruthenium (Ru I) in 1940. In addition unresolved patterns were measured by McNally for 175 lines, but these have never been published.³ Further Zeeman observations were made in 1949 by Meggers with the Bitter magnet at the Massachusetts Institute of Technology. These plates were measured by Kessler in the course of preparing material for the preceding paper. Zeeman data for 32 additional lines obtained from this last set of observations, together with the unpublished material from McNally’s thesis for 175 lines are listed below.The observations were all made with electrodes of 1 part ruthenium powder mixed with 5 parts of silver powder. The experimental conditions and techniques used are fully described by Harrison and McNally.²The wavelengths (in air) of these lines are given in column 1 of

Atomic layer deposition of nanocrystallite arrays of copper(I) chloride for optoelectronic structures

Zinc blende structure γ-copper(I) chloride is a wide bandgap semiconductor with high exciton and biexciton binding energies. γ-CuCl has applications in UV-wavelength optoelectronic structures which can exploit these characteristics, such as 4-wave mixing and optical bistability. For these purposes, a controllable method of achieving thin films and nanocrystallite arrays is necessary. Atomic layer deposition (ALD) of nanocrystallites and thin films of γ-CuCl under restricted conditions has previously been demonstrated. This paper greatly extends the previous work and unequivocally confirms that ALD growth takes place over a range of deposition parameters, as characterised by growth saturation with increasing precursor dose, deposition rate independent of temperature and linear growth rate once a complete film has been formed. Arrays of nanocrystallites of different sizes can be controllably deposited by varying the number of ALD cycles within the initial nucleation region. In this region two distinct growth regimes have been observed depending on the length of the post-chloride precursor purge pulse. Long purge time results in retarded nucleation whereas short pulse time shows enhanced nucleation compared to a strictly linear process. The zinc blende γ-CuCl phase was confirmed with both X-ray analysis and also the signature excitonic Z_1,2 and Z₃ peaks in optical absorption, with no evidence of other impurities. This demonstrates that ALD is a suitable technique for the controllable deposition of thin films and arrays of nanocrystallites of CuCl which may facilitate the use of CuCl in thin film or nanocluster form for further exploration in optoelectronic and photonic applications.     

The First Spectrum of Manganese,Mn I

In 1894, two short series of threefold spectral terms were discovered in the arc spectrum of manganese, and in 1922 other regularities involving fivefold and sixfold terms were discovered by Catalán who coined the word “multiplet” for the group of related lines resulting from combinations of such complex terms. Multiplet analyses of complex spectra promptly led to the present formal quantum interpretation of all such phenomena, but comparable progress in the analysis of the Mn I spectrum was handicapped by the paucity of experimental data.New observations of about 2500 wavelengths and intensities plus 440 Zeeman patterns made available in 1948–49 have now been completely exploited to derive additional atomic energy levels and thereby explain more of the observed Mn I lines. The result is that a total of 42 even terms with 125 levels and 60 g-values have now been designated and allocated to electron configurations, and 94 odd terms with 266 levels, 164 g-values, plus 13 miscellaneous levels. These terms are distributed among four multiplicities (doublets, quartets, sextets, octets), and transitions between even and odd terms account for more than 2030 lines ranging in wavelength from 1785 Å to 17608 Å.     

A Preliminary List of Levels and g-Values for the First Spectrum of Thorium (Th I)

The present state of the analysis of the first spectrum of thorium (Th I) is discussed briefly. Even and odd levels are listed in ​and2.2. The low even levels form terms arising from the configurations 6d² 7s² and 6d³ 7s. The Th I standard wavelengths that fit into the known level arrays are presented in Config.DesignJLevelObs. gLS. g

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6d²7s²a ³F2  0.000.7410.6673  2869.261.0741.0834  4961.661.2121.250a ³P0  2558.060.00   0/01  3865.471.4771.5002  3687.991.2561.500a ¹D2  7280.131.1891.000a ¹G4  8111.001.08  1.0006d³(⁴F)7sa⁵ F1  5563.140.0620.0002  6362.401.0141.0003  7502.291.2531.2506d³(⁴F)7sa ⁵F4  8800.251.3101.3505  9804.811.3661.4006d³(⁴P)7sa ⁵P111601.032.41  2.500211802.941.7211.833312847.971.39  1.6676d³ (²G)7sa ³G313088.571.04  0.750413297.420.98  1.050514204.301.13  1.2006d³ (²D)7sa ³D113962.500.76  0.5006d³(²H)7sa ³H415493.230.92  0.800Open in a separate window

Table 2

Odd energy levels of Th I

液中测量型原子力显微镜的研究

简述了使用临界角角度传感器的探针驱动角度检出型ＡＦＭ的测量原理及在液体中进行测量的原理，并对在空气中和液体中的测量结果进行了分析比较。     

Non-uniform slot injection (suction) into water boundary layers over (i) a cylinder and (ii) a sphere

An analysis is performed to study the effect of non-uniform slot injection (suction) into steady two-dimensional and axi-symmetric laminar boundary layers with variable viscosity and Prandtl number. Non-similar solutions have been obtained from the starting point of the streamwise co-ordinate to the exact point of separation. The difficulties arising at the starting point of the streamwise co-ordinate, at the edges of the slot and at the point of separation have been overcome by applying an implicit finite difference scheme with the quasi-linearization technique and an appropriate selection of finer step size along the streamwise direction. The results indicate that the separation can be delayed by non-uniform slot suction and also by moving the slot downstream but the effect of non-uniform slot injection is just the opposite. The heat transfer rate is found to depend strongly on viscous dissipation but the skin friction is little affected by it.     

Impact toughness of reinforcing steels produced by (i) the Tempcore process and (ii) microalloying with vanadium

A “direct measurement” of the impact toughness of both Tempcore and microalloyed with vanadium reinforcing steel bars, of the same strength class (500 MPa nominal yield stress), is undertaken. The term “direct measurement” means that V-notched specimens with the original round section of the bars (and not with the standard rectangular one) are used, mentioned here as direct V-notched (DVN) specimens. The major complications encountered with them are the use of non-standard geometry (Charpy V-notched, CVN), the variable size of the bars and the composite microstructure of the Tempcore reinforcing steel. It has been shown that the toughness characteristics of reinforcing steels may be estimated by the CVN impact test using direct (DVN) specimens. It is found that if the notch exceeds a critical depth, meaningful measurements may be obtained, regardless of the diameter of the reinforcing steel bar and that the transition temperature may be estimated from the residual fracture angle of direct (DVN) specimens. The microalloyed with vanadium reinforcing steel has a lower temperature-transition range from ductile-to-brittle fracture (−10 °C), compared to the AISI 1020 steel, attributed to the vanadium micro-additions, but it is higher compared to the Tempcore steel (−30 °C).     

Classification of solid dispersions: correlation to (i) stability and solubility (ii) preparation and characterization techniques

Solid dispersion has been a topic of interest in recent years for its potential in improving oral bioavailability, especially for poorly water soluble drugs where dissolution could be the rate-limiting step of oral absorption. Understanding the physical state of the drug and polymers in solid dispersions is essential as it influences both the stability and solubility of these systems. This review emphasizes on the classification of solid dispersions based on the physical states of drug and polymer. Based on this classification, stability aspects such as crystallization tendency, glass transition temperature (T_g), drug polymer miscibility, molecular mobility, etc. and solubility aspects have been discussed. In addition, preparation and characterization methods for binary solid dispersions based on the classification have also been discussed.     

原子吸收光谱仪常见故障的排除(火焰部分)

本文讨论了原子吸收光谱仪常见的故障、产生原因及排除方法。     

Low Even Configurations in the First Spectrum of Ruthenium (Ru I), part 2

A published calculation for the 4d⁸, 4d ⁷5s, and 4d⁶ 5s² configurations of Ru I (R. E. Trees, J. Opt. Soc. Am. 49, 838 (1959).) is repeated in steps. Displacements produced by configuration interaction are evaluated, and departures of term positions from familiar expectations in the absence of configuration interaction are explained. The weaker perturbations produced by second-order effects of the spin-orbit interaction are then determined. It is shown that the neglect of these effects in published hand computations has obscured the remarkably good agreement between theory and observation that is obtainable in spectra of the second long period. The eigenvectors are based on “third-order eigenfunctions” which describe the levels simply, and show the degree of LS-coupling in a more quantitative manner.     

Au-V(Cr)原子线的半金属铁磁性研究

基于第一性原理计算,理论预测到吸附在氮化硼纳米管上的Au-V(Cr)原子线呈现半金属性:费米面上的态密度在多数自旋方向上呈金属性而在少数自旋方向上呈半导体性.吸附在氮化硼纳米管上的Au-V(Cr)原子线的半金属性起源于孤立的Au-V(Cr)原子线.计算得到单原胞的总磁矩为玻尔磁子的整数倍,这也是半金属性的一个显著特征.