Experimental Intensity Ratios Research Articles

Quantitative analysis of the active ingredient in a multi-component tablet formulation by powder X-ray diffractometry

A powder X-ray diffraction technique has been developed for the quantitative analysis of the active ingredient in intact tablets. Carbamazepine (CBZ) was the model drug and the other tablet ingredients were microcrystalline cellulose, starch, stearic acid and silicon dioxide. The integrated intensities of 21 X-ray lines of CBZ were used for the quantitative analysis. The ratio of the intensities of the X-ray lines in these tablets to the intensity of the same lines in tablets containing only CBZ was calculated as a function of the CBZ weight fraction. Such a calculation was based on the mass absorption coefficients of the tablet ingredients. These ratios were also experimentally determined in prepared tablets wherein the weight fraction of CBZ ranged from 0.51 to 0.69. There was a good agreement between the calculated and experimental intensity ratios. The relative error in the determination of CBZ was less than 10%. Small changes either in the compression pressure or in the tablet composition did not affect the validity of the assay method.

Projectile K Auger spectra of Li-, Be-, and B-like multiply charged Ne ions: Auger energies, Auger rates, and intensity ratios.

In this work we have made an intense theoretical effort to determine accurate K-Auger transition energies, Auger rates, and line intensity ratios for Be- and B-like multiply charged neon ions using several different atomic models. Theoretical data on Li-like states in Ne viii are also reported. In particular a detailed study of Auger line intensity ratios is presented. For several Be- and B-like states strong cancellations in the Auger matrix elements are predicted. These rates are quite sensitive to the atomic wave functions. We have also deduced experimental Auger intensity ratios for Be and B-like Ne ions from previous data. In order to classify our high-resolution projectile spectra, theoretical Auger energies and rates for various terms of the electron configurations 1s2${\mathit{s}}^{2}$2${\mathit{p}}^{\mathit{n}\mathrm{\ensuremath{-}}1}$, 1s2${\mathit{p}}^{\mathit{n}+1}$, and 1s2s2${\mathit{p}}^{\mathit{n}}$ (n=1--3) have been calculated relativistically, using the saddle-point technique, the multiconfiguration Dirac-Fock model, and the 1/Z expansion method. Several previously unknown line identifications of Be-like states in Ne vii and B-like states in Ne vi are reported.

The influence of boron distribution on the valence of Eu in EuPd3B

The valence states of europium in EuPd3B are studied in connection with the distribution of boron atoms in the neighbourhood of the Eu ion. The temperature dependence of this distribution, which determines the populations of the Eu3+ and Eu2+ states, is analysed. The results are compared with the experimental intensity ratios of the Mossbauer lines. Fairly satisfactory agreement is obtained.

Determination of the Relative Amounts of α-carbamazepine and β-carbamazepine in a Mixture by Powder X-Ray Diffractometry

AbstractA powder X-ray diffraction technique has been developed to quantify the relative amounts of α-carbamazepine (A) and β-carbamazepine (B) when they occur as a mixture. The theoretical basis of this technique was developed in 1948 by Alexander and Klug (Anal. Chem., 20:886-889). The powder X-ray diffraction patterns of A and B revealed that the line with d-spacing of 10.1 Å was unique to A. The ratio of the integrated intensity of the 10.1 Å line in a mixture of A and B, to the intensity of the 10.1 Å line in a sample consisting of only A, was calculated as a function of weight fraction of A in the mixture. These ratios were also experimentally determined, and there was a good agreement between the theoretical and experimental intensity ratios. The particle size of the samples, the sample preparation technique and the experimental conditions were controlled so as to eliminate the major sources of error in powder X-ray diffractometry. In order to minimize preferred orientation of the particles, a sample holder was specially fabricated.

Tables of Experimental Reference Intensity Ratios Table No. 2, December, 1989

This is a second and considerably expanded edition of the RIR table. We are pleased that considerable interest is now being generated in the RIR table; several contributors have provided measured data for this second edition. We have also added many entries of common minerals and simple compounds from the JCPDS data base and will continue to add more from this source with each succeeding table published. In this regard where we receive requests for a particular class of RIR's (alloys, or rare earth oxides, for examples) we can give higher priority to extracting these values from the JCPDS data base.The reader should refer to the text explanation of the first published table in Vol. 3, No. 4 of this journal. In the first text two important errors are noted here; Equation (3) should have read RIRcorr = RIRobs/Wj; and the second sample preparation category of section 4 Specific Parameters should read “(w) Methods including well mounts with side or back loading or similar process”.

Studies of atomic decay properties using fast ion beam spectroscopy

This paper presents a comparison between experimental and theoretical transition probabilities for resonance lines in the Cu, Na, Mg and Al isoelectronic sequences. Particular emphasis is placed on modern beam-foil studies where detailed cascade corrections have been made. In general, good agreement is observed between theoretical calculations with an extensive treatment of correlation effects and the beam-foil results with an equally extensive treatment of cascades. Some cases where the experimental situation is less complicated will also be mentioned. In particular we discuss the recently observed discrepancy between the experimental and theoretical intensity ratios for the two fine-structure components of the 3s23p 2P-3s3p2 2S resonance transition in the Al-sequence.

Density effects on collision induced Raman scattering in CO2–Ar and CO2–Xe mixtures

The density dependence of the intensity of the CO2 Raman forbidden ν2 band (667.3 cm−1 ) has been studied in the CO2 –Ar and CO2 –Xe mixtures at 40 and 80 °C. The experimental results show that the band intensity increases linearly with density from 0.057 to 0.166 mol/cm3 which indicates that two-particle collisions dominate the scattering process. The intensity of the ν2 band is higher in the CO2 –Xe mixture than that in the CO2 –Ar mixture, and the experimental intensity ratio for the two mixtures is 2.2±0.2. The very good agreement between the experimental intensity ratio and the ratio calculated theoretically for the dipole–quadrupole (Aα) contribution to the collision induced scattering indicates that the Aα mechanism is responsible for the appearance of the forbidden band.

Standardless EDS analysis of bulk and thin specimens.

A direct relationship between the x-ray intensity ratio and the concentration ratio for bulk and thin specimens has been established by use of a revised full-diffusion model of electron scattering. The suitable ionization cross section, the most important parameter influencing the accuracy of the calculated Cliff-Lorimer factors, has been found after comparing the experimental intensity ratio I(L)/I(K) of eight elements (from Ge to Sn) and I(M)/I(L) of six elements (from Sm to Bi) with the calculated values. The quantitative standardless EDS analysis of bulk samples obtained by this direct method is more satisfactory than the commercial indirect method which gives the composition through ZAF correction after calculating the intensity factors of pure elements. The quantitative standardless analysis of thin samples has been improved by the suitable cross section significantly. This method has been applied to the analysis of film on substrate either without any common element or with one common element (P-Si glass film on Si). It has also been used to calculate the intensity factors of pure bulk samples and the backscattering correction factor in Auger electron spectroscopy.

Effect of rotational coupling on emission probabilities of Lyman and Werner band systems of the vacuum ultraviolet spectrum of H2

Ratios of emission probabilities of rotational lines of the Lyman and Werner band systems, B 1∑+u →X 1∑+g and C 1∏u →X1∑+g, respectively, are calculated by different methods. These theoretical ratios are compared to the experimental intensity ratios of about a hundred lines selected from a vacuum ultraviolet emission spectrum whose intensity is investigated for the first time at high resolution. The computation permits to compare two ways of solving a system of two coupled equations with discrete eigenvalues. In most cases the effect of the mutual rotational perturbation between B and C states is found significant on the ratio of P and R line intensities. Ambiguity in labeling a few B and C levels is discussed.

Partial autoionization rates of O4+ (1s2s22p)3P0 and 1P0: A crucial test of electron correlation in Be-like systems.

For the first time, ratios of partial autoionization widths have been measured for highly ionized oxygen projectiles. In particular we have studied the Auger decay of the Be-like (1s2${s}^{2}$2p${)}^{3}$${P}^{0}$ and $^{1}\mathrm{P}^{0}$ states in ${0}^{4+}$ decaying to the 1${s}^{2}$2p and 1${s}^{2}$2s final ionic states. Our experimental intensity ratios for the $^{3}\mathrm{P}^{0}$ and $^{1}\mathrm{P}^{0}$ states are 1.7 and 16, respectively. We also present new results on the partial and total autoionization widths of these states from calculations which include electron correlation and interchannel coupling via the application of the many-electron theory of ionic resonances in terms of complex coordinates.

Pressure-tuning resonance between the vibron and the libron in CH

The Raman spectra of ${\mathrm{CH}}_{2}$${\mathrm{Br}}_{2}$ and ${\mathrm{CD}}_{2}$${\mathrm{Br}}_{2}$ molecular solids have been measured up to 100 kbar in a diamond-anvil cell. The pressure-tuning resonance between the vibron and the libron has been observed for the first time around the crossover pressures of 43 and 66 kbar for ${\mathrm{CH}}_{2}$${\mathrm{Br}}_{2}$ and ${\mathrm{CD}}_{2}$${\mathrm{Br}}_{2}$ molecular solids, respectively. By using the theory of resonance interaction between two states of the same symmetry, we analyzed the frequency behavior of observed vibrational modes as well as the drastic changes in the intensity with pressure: By deuteration (${\mathrm{CD}}_{2}$${\mathrm{Br}}_{2}$) the frequency of the unperturbed libron for ${\mathrm{CH}}_{2}$${\mathrm{Br}}_{2}$ was shifted down by about 21 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ at all pressures. This effect is due to the increase in moment of inertia involving mainly the motion of deuteron atoms, and is the chief cause for the change of the crossover pressure. The coefficients of mixing between the vibron and the libron were calculated at various pressures, and the transfer phenomenon for the Raman intensity was investigated by comparison to the experimental intensity ratio.

M4,5N6,7XAuger spectra of free Yb atoms

${M}_{4,5}{N}_{6,7}X$ ($X={N}_{6,7} or {O}_{2,3}$)-type normal and vacancy satellite Auger spectra of atomic ytterbium have been measured with the use of electron impact excitation. The main Auger spectra have been analyzed and compared with the calculated results. The relative energies and intensities of the lines have been calculated in the nonrelativistic mixed-coupling scheme applying $\mathrm{jj}$ coupling to the initial and the intermediate coupling to the final states of the Auger transitions. The kinetic energies have also been calculated in the relativistic intermediate coupling with the use of the Dirac-Fock program of Grant . The experimental intensity ratio between the ${M}_{5}$ and ${M}_{4}$ line groups is found to be 3.0, which deviates strongly from the statistical ratio 1.5 due to ${M}_{4}{M}_{5}X$ Coster-Kronig processes. For the same reason, a strong satellite structure appears also at the low-energy side of the main ${M}_{5}{N}_{6,7}{N}_{6,7}$ line group.

N4,5N6,7X Coster-Kronig spectra of free Hg atoms

The N4,5N6,7X (X=N6,7, O2,3, O4,5) Coster-Kronig-type Auger spectra of free mercury atoms have been measured and analysed by comparing the experimental results with the calculated profiles. The spectra have been measured with the use of electron beam excitation. The kinetic energies of the Auger lines have been calculated by the Delta SCF method using a relativistic Dirac-Fock program. The relative energies of the line components have also been computed non-relativistically and a comparison has been made between the non-relativistic and the relativistic results. The intensities of the lines have been calculated in the mixed coupling scheme applying jj coupling to the initial states and intermediate coupling to the final states. The calculated profile reproduces the fine structure in the experimental spectrum rather well. The experimental intensity ratios between different line groups are between the experimental results of Matthew et al. (1980) and Larkins et al. (1977) for solid Au, and in obvious discrepancy with the calculated group intensity ratios based on McGuire's results (1974).

Detection of muonic Auger electron lines from silver

Muonic K- and L-Auger transitions in Ag have been measured with cooled Si p-n junction detectors of high resolution. The experimental Auger intensity ratios are compared with calculated values.

Quantitative determination of argon in sputtered films by wavelength‐dispersive electron probe microanalysis

AbstractA method is described for the calibration of Ar Kα counting rates, measured using crystal spectrometers equipped with Ar‐flow proportional counters. Linear extrapolation from overvoltage corrected x‐ray yields of the elements with Kα x‐ray energies lower than those of the ArK absorption edge gives an accurate description of the experimental Ar Kα intensity ratios from counters operated at different values of gas pressure. Results of all‐element film analyses provided by a matrix correction procedure, ZAF, indicate an accuracy better than 5% relative for the determination of Ar concentrations ranging from 0.1 to 10 wt%.

Empirical atomic sensitivity factors for quantitative analysis by electron spectroscopy for chemical analysis

AbstractQuantitative information from electron spectroscopy for chemical analysis requires the use of suitable atomic sensitivity factors. An empirical set has been developed, based upon data from 135 compounds of 62 elements. Data upon which the factors are based are intensity ratios of spectral lines with F1s as a primary standard, value unity, and K2p3/2 as a secondary standard. The data were obtained on two instruments, the Physical Electronics 550 and the Varian IEE‐15, two instruments that use electron retardation for scanning, with constant pass energy. The agreement in data from the two instruments on the same compounds is good. How closely the data can apply to instruments with input lens systems is not known. Calculated cross‐section data plotted against binding energy on a log‐log plot provide curves composed of simple linear segments for the strong lines: 1s, 2p3/2, 3d5/2 and 4f7/2. Similarly, the plots for the secondary lines, 2s, 3p3/2, 4d5/2 and 5d5/2, are shown to be composed of linear segments. Theoretical sensitivity factors relative to F1s should fall on similar curves, with minor correction for the combined energy dependence of instrumental transmission and mean free path. Experimental intensity ratios relative to F1s were plotted similarly, and best fit curves were calculated using the shapes of the theoretical curves as a guide. The intercepts of these best fit curves with appropriate binding energies provide sensitivity factors for the strong lines and the secondary lines for all of the elements except the rare earths and the first series of transition metals. For these elements the sensitivity factors are lower than expected, and variable, because of multi‐electron processes that vary with chemical state. From the data it can be shown that many of the commonly‐accepted calculated cross‐section data must be significantly in error—as much as 40% in some cases for the strong lines, and far more than that for some of the secondary lines.

Core level shake up structures of N 2 adsorbed on nickel surfaces: Cluster models

Self-consistent Hartee-Fock-LCAO calculations on a linear NiN 2 cluster are used to explain the two-peak structure observed in core level photoemission from N 2 adsorbed on the Ni (100) surface. The two observed peaks are due to different N 2 core hole final states, a screened and an unscreened final state that can be clearly identified in the cluster model. The energy separation and intensity ratio (computed using the sudden approximation) of the two final states in NiN 2 are comparable with the experimental peak separation and intensity ratio for reasonable cluster geometries. A comparison with previous model studies on NiCO is used to explain the different shape of the core level spectra of N 2 and CO adsorbed on nickel surfaces.

Experimental X-ray intensity ratios of the Lα Lβ, Lγ, Lℓ and Lη lines

Experimental, relative intensities for the components of L X-rays have been collected from the literature, and the atomic number dependence has been found for the Lβ/Lα, Lγ/Lα, Ll/Lα and Lη/Lα ratios. Among the L X-ray components Lα is predominant if Z 1.0 if Z≈100.

Differences in L2,3MM Auger electron spectra of atomic and metallic manganese

The L 2,3 MM Auger electron spectra of manganese vapour and metal have been measured using 3-keV electron beam excitation. The transitions have been qualitatively interpreted within the one-electron model with two-hole coupling. The experimental intensity ratios of the groups L 2,3 M 1 M 2,3: L 2,3 M 2,3 M 2,3: L 2,3 M 2,3 M 4,5 : L 2,3 M 4,5 M 4,5 have been found to be 0.9:3.1:3.2:1.0 for the vapour phase and 0.4:0.6:1.3:1.0 for the solid phase. The L 2 -group intensities in the solid-phase spectrum are lower than the L 3-group intensities by 1 10 , while in the vapour-phase spectrum the intensity ratio L 3 MM/ L 2 MM increases from 4 for the M 4,5 M 4,5 final state to 7 for the M 2,3 M 2,3 final state. The binding energies obtained for the L 2 and L 3 levels of free manganese atoms are 664.2±0.5 and 651.9±0.5 eV, respectively. The vapour—metal energy shifts are found to be ∼20 eV for the inner-shell and ∼19 eV for the outer-shell final state. The change in extra-atomic relaxation on going from the one-hole to the two-hole state is discussed in terms of the Auger parameters.

Infrared and Raman intensities of polyethylene and perdeuteropolyethylene: Factor group splittings

In a previous work we have calculated the infrared and Raman intensities of polyethylene applying the electro-optical parameters obtained from simple molecules to a model of single and isolated chains. In this work the validity of such an approximation is discussed. From the comparison of the calculated and experimental intensity ratios of the components of factor group splittings it is concluded that a Hornig’s-type gas oriented model with no sizeable electrical interactions between molecular chains accounts for the observed infrared and Raman data.