Hyperfine structure of atomic spectra

Valuable results have been attained with these programs, but much more is possible in the future. For one there are the term values of highly ionized heavy atoms, which are difficult to access experimentally, but also the corresponding transition probabilities important for the explicit simulation of a high-temperature plasma. Another aspect, which has attracted attention, is the hyperfine structure of atomic spectra and with it the determination of nuclear moments in the combination of computation and high-resolution experiments. 

Electrodeless discharge lamps (EDL), powered with energy in the radio-frequency range, were used as early as 1928 by Jackson, and in 1948 Meggers used them to determine hyperfine structure of atomic spectra. These lamps produce narrow-line, high-intensity spectra with little self-absorption. They would appear, therefore, to be promising sources for atomic absorption. 

The most important characteristic of ESR spectra is their hyperfine structure. The number, position and width of the lines in the spectra depend on the nature and on the conformation of the radical. The hyperfine structure of the spectra results from interaction of the unpaired electron with neighbouring atoms possessing resultant nuclear spin. When these are only hydrogen atoms... 

Takahashi et al. [25] reported that the dispersed tetravalent vanadium (l 7/2) showed a hyperfine structure but broad band could be observed in the agglomerated vanadium. Miyamoto et al. [8] and Jhung et al. [7] reported that EPR spectra of VAPO -S showed hyperfine structure. Miyamoto et al. [8] suggested that the hyperfine structure indicated atomically dispersion of vanadium in VAPO -S molecular sieve, in other words, vanadium was substituted in the framework of AIPO -S. 

In the present experiment, we are concerned with the hyperfine structure of the ben-zosemiquinone radical anions. The delocalized unpaired tt electron is of course distributed over the entire molecular frame of six C atoms and two O atoms. With R = H, by symmetry, it is clear that the four protons are all equivalent in the para species hence five hyperfine lines with relative intensities 1 4 6 4 1 are expected in the ESR spectrum of this radical. By contrast, when R is not a proton, the three ring protons are not related by symmetry, and thus each may be expected to possess a different splitting constant. A hyperfine structure pattern of eight unequally spaced lines of equal intensity is expected. The line splittings and relative intensities in ESR spectra thus convey information about the geometric arrangement of the atoms. 

Excellent general survey for chemists, physicists specializing in other fields. Partial contents simplest line spectra and elements of atomic theory, building-up principle and periodic system of elements, hyperfine structure of spectral lines, some experiments and applications. Bibliography. 80 figures. Index, xii 257pp. 5 6 x 8- "Paperbound 2.00... 

Compute from this both the distribution of the sum of all the tt electrons, i.e. the distribution iv of the overall electron density over the three carbon atoms in the radical, as weU as the distribution qr of charge over the ions. Calculate the distribution Qr of electron spins in the radical. This quantity is called the spin density g>r- It can be determined for example from the hyperfine structure of electron-spin resonance (ESR) spectra. 

The fine structure of atomic line spectra and the hyperfine spectra of the electronic Zeeman effect is characterized by a symmetric splitting of the primary lines. The nuclear Zeeman interaction symmetrically splits the spectral line, and it is easy to predict from the well-established nuclear Zeeman relationship, which... 

The fine structure of atomic line spectra and the hyperfine splittings of electronic Zeeman spectra are non-symmetric for those atomic nuclei whose spin equals or exceeds unity, / > 1. The terms of the spin Hamiltonian so far mentioned, that is, the nuclear Zeeman, contact interaction, and the electron-nuclear dipolar interaction, each symmetrically displace the energy, and the observed deviation from symmetry therefore suggests that another form of interaction between the atomic nucleus and electrons is extant. Like the electronic orbitals, nuclei assume states that are defined by the total angular momentum of the nucleons, and the nuclear orbitals may deviate from spherical symmetry. Such non-symmetric nuclei possess a quadrupole moment that is influenced by the motion of the surrounding electronic charge distribution and is manifest in the hyperfine spectrum (Kopfer-mann, 1958). 

For the investigation of atomic spectra in most cases Doppler-limited resolution is sufficient to separate spectral lines. Sub-Doppler spectroscopy is only required if the substructure of lines, caused by narrow fine structure or by hyperfine structure is to be resolved, or if very accurate line positions, line profiles or line shifts are to be measured. 

Moseley s law spect The law that the square-root of the frequency of an x-ray spectral line belonging to a particular series is proportional to the difference between the atomic number and a constant which depends only on the series. mOz-lez, 10 Mossbauer spectroscopy spect The study of Mossbauer spectra, for example, for nuclear hyperfine structure, chemical shifts, and chemical analysis. mus,bau-3r spek tras ko pe ... 

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