Hyperfine structure measurements in Kr II

The fast ion beam laser technique has been utilized to study the hyperfine structure in the transitions 4d ⁴ D _7/2-5p ⁴ D ₇ ^2/0 at 6420 Å and 4d ⁴ D _7/2-5p ⁴ D ₅ ^2/0 at 6303 Å in singly-charged krypton. The magnetic dipole and electric quadrupole hyperfine constants have been extracted for the upper levels of the transitions.     

Hyperfine structure studies of Tantalum

A narrow bandwidth ring dye laser pumped by an argon ion laser has been used to investigate the hyperfine structure of the even and odd parity levels of tantalum by optogalvanic spectroscopy in the wavelength range 5640 to 6050 Å. Seventeen transitions have been observed and eight of these have not been reported in the literature so far. These transitions involve 27 levels with 15 odd and 12 even parity configurations. The magnetic dipole hyperfine interaction constants A and the electric quadrupole interaction constants B for these levels have been computed and compared with the data available in literature. The results for the levels at 34799.71 cm^?1, 26960.46 cm^?1 and 19657.78 cm^?1 are reported for the first time.     

Hyperfine structure in Ga NQR of Gas and GaSe

Fine structure is reported in the ^69,71Ga NQR spectra of GaS and GaSe. The ⁶⁹Ga (I = ³₂) and ⁷¹Ga (I = ³₂) spectra are $\text{qualitatively}$ different for each compound. This is attributed to an indirect spin-spin interaction between nearest-neighbour Ga atom pairs. A model giving reasonable quantitative agreement with experiment is presented.     

Hyperfine structure measurements of103Rh

Hyperfine structure has been measured in 28 states of¹⁰³Rh below 34,000 cm^?1. The magnetic dipole interactionA constants in the metastable states 4d ⁸ 5s ⁴ P _5/2,3/2,² P _3/2,1/2,² D _5/2,3/2,² G _9/2,7/2 and 4d ⁷ 5s ^{2 4} F _{9/2,7/2,5/2,3/2} have been determined using the laser radio-frequency double-resonance method and in the states 4d ⁸ 5p ⁴ D _{7/2,5/2,3/2,1/2},⁴ G _7/2,5/2,⁴ F _{9/2,7/2,5/2,3/2},² G _9/2,7/2,² F _7/2,5/2 and² D _5/2,3/2 by high-resolution laser spectroscopy.     

Hyperfine structure of atoms in combined external fields

In order to interpret experimental hyperfine spectra of the resonance lines of the alkali atoms in presence of external electric and magnetic fields in arbitrary direction relative to each other a computer programme has been developed which computes the splitting of hyperfine components of spectral lines and their expected relative transition probabilities. The computed data can be directly compared with experimental spectra taken by laser-atomic-beam spectroscopy. Splitting parameters, like hyperfine structure constants or polarizabilities, can be evaluated with the help of a fitting procedure. The theoretical approach used in the programme has rather general validity, therefore the programme can be utilized, within the validity of the applied theoretical assumptions, for any kind of atom.     

Hyperfine structure in fluoroform by beam master spectroscopy

The hyperfine structure of the J = 1 → 0 rotational transition of the CF₃H molecule has been investigated with a high-resolution beam-maser spectrometer. The hyperfine coupling constants have been evaluated.     

Hyperfine structure observed in EPR spectra of polyphenylacetylene solutions

The high-temperature (>120C) electron paramagnetic resonance (EPR) spectrum of solutions of polyphenylacetylene have been deconvoluted into the spectra of two separate radicals, a delocalized π radical, whose EPR spectrum consists of a single 15-G wide Gaussian line comprising about 90% of the total signal and a second, more localized π radical exhibiting complex hyperfine structure in its EPR spectrum. Some possible structures for the minor component radical are suggested and their hyperfine splitting constants calculated using molecular orbital theory.     

Hyperfine structure in low-lying levels of PtII,AuII and BiII

Far UV lines in the spectra of PtII, AuII and BiII emitted by a hollow-cathode lamp exhibit Fabry-Perot patterns, which are used for determining the hyperfine structure of the low-lying levels of these three spectra and the isotopic shifts in five lines of PtII. The experimental data are compared with those computed through the relativistic Dirac-Fock method. The effect of spin polarisation is discussed. In the case ofd electrons the Hartree-Fock method with spin polarisation is used for explaining the large ratio between the spin polarisation and relativistic effects.     

Hyperfine structure of some near-infrared Xe I and Xe II lines

This work reports on the experimental determination of the hyperfine splitting of the Xe I lines at 828.01 nm and 834.68 nm and the Xe II line at 834.72 nm. Measurements were performed by means of Doppler-free saturation spectroscopy in a low-pressure radio-frequency discharge. The absolute wavelength of all hyperfine components is obtained by way of a high-precision wavemeter backed-up with the absorption spectrum of the NO₂ molecule. We provide an accurate estimate of hyperfine constants for the lower level of the Xe II transition at 834.72 nm. The two Xe I transition outcomes of our experimental study are compared with data available in the literature.     

Electronic structure investigations of quasicrystals

We present a review of the determination of density of states (DOS) of quasicrystals using valence band photoemission spectroscopy. The absence of fine or spiky structure in the angle-integrated DOS of quasicrystals suggests the possibility of delocalized electronic states. These were confirmed with angle-resolved photoemission studies, which clearly establish the presence of dispersing features attributed to momentum-dependent bandstructure. Such dispersing states are observed not only for deeper-lying sp states, but also for d-derived bands near the Fermi level. Data from three different high symmetry surfaces of decagonal Al–Ni–Co, an ideal model system, are presented. We find that only a few dominant reciprocal lattice vectors are sufficient to describe the quasiperiodic potential, and the implications for electronic properties are discussed.     

Hyperfine structure of Mn II by fast ion beam-laser spectroscopy

We report the first measurements of the hyperfine splitting of the fine structure levels 3d ⁵'4s a ⁵ S ₂ and 3d ⁵ 4p z ⁵ P _1,2,3 ⁰ in singly ionised manganese in a collinear fast ion beam-laser experiment. The ions are excited by the intracavity frequency doubled output of a ring dye laser. The observed linewidth is sufficiently narrow to identify all hyperfine components of each fine structure level.     

Hyperfine structure of13C and15N nuclei in EPR spectra of phosphiniminoxyls

Conclusions The EPR spectra of some chemically and electrochemically generated phosphoniminoxyls were studied. The hyperfine coupling constants on the¹³C and¹⁵N nuclei were determined.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 696–698, March, 1984.A calculation of the distribution of the spin density in these radicals by the PCILO method will be made later.     

Hyperfine structure and isotope shift of some even parity levels in the YbI spectrum

Using laser induced fluorescence spectroscopy the hyperfine structure of the even parity levels 4f ¹⁴6s6d ³ D ₁, 4f ¹⁴ 6s8s ³ S ₁ and 4f ¹³ 5d6s6p (7/2, 5/2)J=1,2,3 as well as of the odd parity level 4f ¹⁴ 6s6p ³ P ₂ in neutral ytterbium has been investigated. The isotope shift of the transitions 4f ¹⁴6s6p ³ P ₀ → 4f ¹⁴ 6s6p ³ D ₁ and 4f ¹⁴ 6s6p ³ P ₂ → 4f ¹⁴ 6s8s ³ S ₁, 4f ¹³ 5d6s6p (7/2, 5/2)J=1,2,3 could be measured with high accuracy. The results for the 4f ¹⁴ 6s6p ³ D ₁ level show a considerable influence of second order effects of the hyperfine interaction. The isotope shifts of the 4f ¹⁴ 6s8s ³ S ₁ and 4f ¹³ 5d6s6p (7/2, 5/2)J=1 levels indicate a possible configuration mixing for these levels.     

Hyperfine structure of the electron paramagnetic resonance spectra of metal ketyls

Summary It was shown, by analyzing HFS in the EPR spectra of various metal ketyls, that the stabiliry of free radicals of the given type is determined by different factors. In aromatic metal ketyls the stabilizing factor is the considerable delocalization of the unpafred electron. In aliphatic metal ketyls the unpaired electron is mainly localized on the carbonyl carbon, and steric factors are more important than delocalization. In mixed ketyls of the type of trimethylacetophenone and benzoylferrocene K-ketyls, both factors act to a commensurable degree.Translated from Zhurnal Strukturnoi Khimii, Vol. 3, No. 5, pp. 536–540, September–October, 1962