The effects of modulation frequency and rf ENDOR power on 53Cr3+ ENDOR lines in CsAl sulfate alum

1980 ◽  
Vol 58 (5) ◽  
pp. 687-692 ◽  
Author(s):  
A. Manoogian ◽  
B. W. Chan
Keyword(s):  
Single Crystals ◽  
Line Intensity ◽  
Modulation Frequency ◽  
Spectral Lines ◽  
Double Quantum ◽  
Frequency Interpretation ◽  
Lorentzian Form

An investigation was made of the effects of modulation frequency and rf ENDOR power on the single and double quantum ENDOR spectral lines of 53Cr3+ ions in single crystals and powders of CsAl sulfate alum. Measurements were made of the linewidths and intensities in the single crystals and of the linewidths in the powders. It was found in the single crystals that a factor of 2/1 exists for the ratio of single/double quantum linewidths at the limit of zero ENDOR power and modulation frequency. Interpretation of the line intensity results with the results of lineshape theory indicates that the ENDOR lines are of Lorentzian form, at least for low values of ENDOR power.

Photoluminescence Spectral Lines Identification in Ho3+-, Er3+-, and Tm3+-doped MgxZn1–xSe Single Crystals

1999 ◽  
Vol 14 (4) ◽  
pp. 1227-1234 ◽  
Author(s):  
Young-Geun Kim ◽  
Ho-Jun Song ◽  
Seok-Kyun Oh ◽  
Wha-Tek Kim ◽  
Kwang-Ho Park ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Single Crystals ◽  
Energy Levels ◽  
Wurtzite Structure ◽  
Spectral Lines ◽  
Photoluminescence Spectra ◽  
Closed Tube ◽  
Sublimation Method ◽  
The Rare Earth

MgxZn1-xSi: Ho3+, MgxZn1-xSe: Er3+, and MgxZn1-xSe: Tm3+ single crystals were grown by the closed-tube sublimation method. The single crystals crystallized into a zincblende structure at the composition x = 0.11 and a wurtzite structure at the composition x = 0.25, 0.32, and 0.41. The trivalent ions (Ho3+, Er3+, and Tm3+) of the rare-earth elements Ho, Er, and Tm site in Td and C3v symmetries in the single crystals with zincblende and wurtzite structures, respectively. Sharp emission peaks appeared in the photoluminescence spectra of the single crystals. These emission peaks are identified to originate from the radiation recombination between the energy levels of the trivalent ions sited in Td and C3v symmetries.

scholarly journals On the polarisation of electrons by scattering

1932 ◽  
Vol 136 (830) ◽  
pp. 638-651 ◽  
Keyword(s):  
Magnetic Field ◽  
Single Crystals ◽  
Uncertainty Principle ◽  
Magnetic Moment ◽  
Coherent Scattering ◽  
Spectral Lines ◽  
X Rays ◽  
Negative Results ◽  
Polarised Light ◽  
The Waves

The possibility of demonstrating the spin of the electron directly has been discussed since the first growth of wave mechanical conceptions, and the ascription of a magnetic moment to the electron to explain doubling of spectral lines. Bohr has shown, however, that any experiment designed to do this by deflection in a magnetic field, in any manner similar to that used by Gerlach and Stem to measure the magnetic moment of atoms, must fail owing to the operation of the Uncertainty Principle. It does not seem, however, that this will hinder us from demonstrating an asymmetry in the electron by means of scattering experiments; the method is closely analogous to the asymmetric scattering of polarised light, and was in fact used by Barkla to show the polarisation of X-rays. The earlier experiments which were carried out on the polarisation of electrons by Wolf, by Joffé and Arsenieva and by Davisson and Germer all led to negative results. The very careful work of Davisson and Germer should be specially mentioned, in that they reflected electrons from the faces of single crystals at angles corresponding to coherent scattering of the waves. Working up to a velocity of 120 volts they found no asymmetry in the scattering more than ½ per cent., which was within the limit of error of the apparatus. Darwin has shown, however, that no polarisation is to be expected in this type of experiment.

scholarly journals Transition probability ratios in the Mg I 3p-4s transition

2004 ◽  
pp. 45-48 ◽  
Author(s):  
Stevan Djenize ◽  
Aleksandar Sreckovic ◽  
Srdjan Bukvic
Keyword(s):  
Experimental Data ◽  
Excellent Agreement ◽  
Line Intensity ◽  
Transition Probability ◽  
Plasma Source ◽  
Low Pressure ◽  
Spectral Lines ◽  
Relative Line Intensity ◽  
Relative Line ◽  
Pulsed Arc

Using the relative line intensity I ratios of the astrophysically important 518.360 nm, 517.268 nm and 516.732 nm neutral magnesium (Mg I) lines in the 3p 3Po 0,1,2 - 4s 3S1 transition we have obtained the ratios of corresponding transition probability values (Einstein's A values). They represent the first experimental data based on the analysis of the emission spectral lines. The linear, low-pressure, pulsed arc was used as a plasma source operated in the helium with magnesium atoms introduced as impurities from discharge electrodes, providing there is no self-absorption within the investigated range of Mg I spectrum. We have found excellent agreement with theoretical transition probability ratios tabulated by NIST (2003).

Intensities of the K, L, and M Spectral Lines for the Elements with Atomic Numbers 16 TO 92*

1959 ◽  
Vol 3 ◽  
pp. 109-129
Author(s):  
William J. Campbell
Keyword(s):  
Atomic Number ◽  
Line Intensity ◽  
Thin Layers ◽  
Spectral Lines ◽  
Spectrochemical Analysis ◽  
Background Ratio ◽  
High Line ◽  
Class 1 ◽  
Limited Application ◽  
Very High

AbstractLine intensity and background measurements were made on the K lines for the elements with atomic numbers 16 to 60, L lines for the elements above atomic number 42, and M lines for elements above atomic number 80. Three general classes of samples were investigated: (1) infinitely thick, (2) microgram deposits, and (3) thin layers.These studies show that longer-wavelength L radiation may be preferable to the K series lines from the same element in the range of elements with atomic numbers 42 to 60, In particular the Lα lines are more intense than the K series lines from Class 2 and 3 samples. With Class 1 samples the Lα lines are weaker than the K series but their line-to-background ratio is superior to the K series.M series lines show little promise for spectrochemical analysis except for elements with atomic numbers 90 to 92; for example, with uranium samples in Class 2 and 3, the very high line-to-background ratio of the UMβ1 line may have limited application.Elements with atomic numbers from 16 to 22 are more sensitive than expected due to the very high line-to-background ratios and the reduced collimation requirements in this longwavelength region.

Dynamic Polarization in Single Crystals of CaF2 Containing H Atoms as Paramagnetic Impurities

1969 ◽  
Vol 24 (11) ◽  
pp. 1737-1745
Author(s):  
P. Zegers
Keyword(s):  
Single Crystals ◽  
Spin System ◽  
Nuclear Spin ◽  
Microwave Power ◽  
Modulation Frequency ◽  
Thermal Contact ◽  
Dynamic Polarization ◽  
Spin Temperature ◽  
Nuclear Spin System ◽  
Paramagnetic Centres

Formulae for dynamic polarization in solids having an inhomogeneous electron spin system and a nuclear spin system which can be described by one single spin temperature were derived. It was assumed that the spin temperature, in the rotating frame of those paramagnetic centres which fulfil ωe=ω+ωn or ωe = ω-ωn j can increase due to thermal contact with the nuclear spin- system brought about by high microwave power. Field fluctuations, at the positions of the para­magnetic centres, due to relaxation flipping of surrounding nuclei and paramagnetic centres were also taken into account. Formulae obtained for the enhancement and polarization time as a func­tion of microwave power and for the enhancement as a function of field modulation frequency and -amplitude agreed well with the experimental results in CaF2 single crystals containing H atoms.

scholarly journals Measuring the intensity of spectral lines from discrete counts of line spectra

2021 ◽  
Vol 25 (4) ◽  
pp. 350-357
Author(s):  
P.V. Vashchenkо ◽  
◽  
V.A. Labusov ◽  
◽  
◽  
...  
Keyword(s):  
Measurement Error ◽  
Spectral Line ◽  
Line Intensity ◽  
Atomic Emission ◽  
Linear Interpolation ◽  
Intensity Measurement ◽  
Spectral Lines ◽  
Emission Spectrometry ◽  
Optimal Size ◽  
Photodetector Arrays

In atomic emission spectrometry, photodetector arrays are widely used in spectrum analyzers. A spectrum obtained with detectors of this type is a discrete sequence of digital values of photocell output signals. One way to quantify the concentration of an element in a test sample is to measure the intensity of its analytical line by integrating a region of the spectrum over several counts in the vicinity of this line or by approximating a region of the spectrum with a line shape profile. As a rule, due to the high saturation of atomic emission spectra with spectral lines, the region for calculating the spectral line intensity is limited to several counts. In the case of spectral line drift relative to the photocells of photodetector arrays, this limitation leads to an intensity measurement error, which is the greater, the smaller the number of counts used in integration. The objectives of this study are to determine the optimal size of the computational domain and develop an optimal method for calculating the line intensity to reduce the intensity measurement error. To simulate the drift of spectral lines relative to photocells, we have simulated and recorded a set of spectra of a hollow cathode lamp (Cu, Zn) with different positions of spectral lines relative to the photocells of BLPP-2000 and BLPP-4000 photodetector arrays. In each next spectrum of the set, the spectral lines were shifted relative to those in the previous spectrum by 2 and 1 μm for BLPP-2000 and BLPP-4000, respectively. It has been shown that compared to stepwise interpolation, linear interpolation significantly reduces the effect of the drift of spectral lines on the RMSD of the measured intensities for both types of arrays. In addition, this effect can be further decreased by choosing an optimal range of integration. In the linear interpolation for the selected spectral lines, the minimum measurement error due to the spectrum drift relative to the photocells of photodetector arrays for BLPP-2000 is 0.25 and 0.23% for a range of integration of 1.6 and 3.1 counts, respectively, and for BLPP-4000, it is 0.4 and 0.28% for 1.0 and 2.7 counts, respectively.

Giant burst of the emission line intensity of spatially indirect excitons in GaAs/AlGaAs double quantum wells

2000 ◽  
Vol 42 (8) ◽  
pp. 1535-1541 ◽  
Author(s):  
E. S. Moskalenko ◽  
V. V. Krivolapchuk ◽  
A. L. Zhmodikov
Keyword(s):  
Quantum Wells ◽  
Emission Line ◽  
Line Intensity ◽  
Double Quantum ◽  
Indirect Excitons
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