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1.
J. Maier C. S. Kischkel M. Baumann 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1991,21(2):145-151
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. 相似文献
2.
L. Broström A. Kastberg J. Lidberg S. Mannervik 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1996,36(2):125-127
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. 相似文献
3.
Nisar Ahmad M. Akram K.P. Gill S.P. Asdaq R.M. Akhtar M. Saleem M.A. Baig 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1997,41(3):159-163
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. 相似文献
4.
Molecular candidates possessing unconventional chemical bonding paradigms (e.g., boron wheels, molecular stars, and multicenter bonding) have attracted a great deal of attention by the computational community. The viability of such systems is necessarily assessed through the identification of the lowest lying energy forms of a given chemical composition on the potential energy surface (PES). Although dozens of search algorithms have been developed, only a few are general and simple enough to become standard everyday procedures for this purpose. The simple random search and genetic algorithm (GA) are among these: but how do these approaches perform on typical isomeric searches? The performance of three specific variants for the ab initio exploration of the PES of prototype planar tetracoordinated and hypercoordinated carbon-containing systems C2Al4 and CB62− are compared. The advantages of preoptimizing with a low-cost semiempirical method (e.g., PM6) together with the most cost-efficient GA-based variant are discussed, and the trends verified by the isomer search of the larger Si5Li7+ clusters. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011 相似文献
5.
H. Yuki K. Nakazawa T. Ohtsuki J. Kasagi T. Mitsugashira 《Journal of Radioanalytical and Nuclear Chemistry》1999,239(1):151-153
Low-lying excited levels of231Th fed through α-decay of235U were investigated by using α-γ and γ-γ coincidence technique. From the analyses for co-relating energy levels and transition
intensities, we found that the most favorable transition from 205.3 keV ([631]7/2) level that is fed by the most dominant
α transition from235U is 19.6 keV transition (205.3 keV [631]7/2−→185.7 keV [631]5/2−). We also found that the transition probability of 109.2 keV, 205.3 keV [631]7/2−→96.1 keV [633]9/2+, was corrected to be weak. These findings can explain why the 185.7 keV γ-ray is so strongly observed, 0.57 photons/ga, in
the γ-spectrum associated with the α-decay of235U. The decay scheme of231Th levels previously reported has been modified according to the present analysis. 相似文献
6.
Fine structure is reported in the 69,71Ga NQR spectra of GaS and GaSe. The 69Ga (I = 32) and 71Ga (I = 32) spectra are 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. 相似文献
7.
8.
C. Bengtsson L. Fraenkel T. Olsson 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1987,5(2):147-150
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. 相似文献
9.
M. Musso 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1992,24(3):203-210
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. 相似文献
10.
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. 相似文献
11.
W. M. Whitte E. T. Kang P. Ehrlich J. B. Carroll R. D. Allendoerfer 《Journal of polymer science. Part A, Polymer chemistry》1981,19(4):1011-1020
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. 相似文献
12.
The hyperfine structure splittings in the excited 4f 146s6d states of171Yb and173Yb have been measured. Isotope selection was achieved by stepwise laser excitation of the1 D 2 and3 D 2, 1 states. The3 D 3 state of171Yb was excited via collisional excitation of an intermediate level. The magnetic and electric hfs coupling constants are given and compared to ab initio values calculated from relativistic self-consistent-field wavefunctions. 相似文献
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14.
E. Stachowska M. Fabiszisky M. Christ A. Scholz U. Sterr W. Ertmer 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1993,27(4):303-306
Using two-step laser spectroscopy with the sideband technique the hyperfine structure (hfs) splittings of the levels (3d 4)3 G 4,5 in47Ti have been measured. These are the first hfs measurements of the levels belonging to the 3d N+2 configuration of the system (3d+4s) N+2. The experimental results indicate a strong increase of the core polarization effect due to excitation of both 4s-electrons to the open 3d-shell. 相似文献
15.
This report presents some examples of detailed and systematic studies on diatomic molecules applying microwave and laser spectroscopy and a combination of both. The high quality of the whole data set allows the analysis of small higher order isotope effects which are attributed to the breakdown of the Born-Oppenheimer approximation and to the recently introduced field shift. Examples of molecular groups with different numbers of valence electrons are given for systematic comparison. To interpret the electronic structure of diatomics in a simple configuration model the quadrupole hyperfine coupling is reviewed for the interhalogens in the ground and an excited electronic state. Some preliminary remarks are included about the possibility to investigate hyperfine coupling of repulsive states by the observation of the hyperfine structure of homogeneously predissociating states. 相似文献
16.
E. Pawelec S. MazouffreN. Sadeghi 《Spectrochimica Acta Part B: Atomic Spectroscopy》2011,66(6):470-475
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. 相似文献
17.
Han H Suo B Xie D Lei Y Wang Y Wen Z 《Physical chemistry chemical physics : PCCP》2011,13(7):2723-2731
Configuration-based multi-reference second order perturbation theory (CB-MRPT2) and multi-reference configuration interaction with single and double excitations (MRCISD) have been used to calculate the bending and dissociation potential energy curves (PECs) of ozone. Based on these PECs, equilibrium structures, vertical and adiabatic transition energies of the ground state and several low-lying excited states, as well as intersections and avoided crossings among the states displayed on the PECs are investigated. The energy separation of the open and ring structures and the dissociation energy of the ground state X(1)A(1) are determined by reference-selected MRCISD. Furthermore, one-dimensional cuts along the dissociation reaction coordinate for the lowest four electronic states of O(3) with (1)A' symmetry and possible pre-dissociations are studied. The Hartley band may be pre-dissociable, and the pre-dissociation limit is found to be 3871 cm(-1), which corresponds to symmetric stretching quanta n(ss) ≈ 6. 相似文献
18.
19.
R. Hucke P. H. Heckmann E. Träbert 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1988,9(1):37-45
Decay curves of the Lyman alpha and beta and Balmer alpha transitions in foil-excited Li++ ions have been recorded for incident ion energies 0.1 to 1.3 MeV/amu. The curves have been analyzed with the aim of learning about the relative level populations ofn=2, 3 and 4 levels after ion-foil interaction. The results at the optimum beam energy for the production of the hydrogen-like ion tie in with an earlier isoelectronic study which showed aZ dependence of the population parameters. The data obtained for the range of velocities studied here may in addition be interpreted as to give evidence of a velocity effect of the population mechanism. 相似文献
20.
M. Elantkowska A. Bernard J. Dembczyński J. Ruczkowski 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1993,27(2):103-109
The hyperfine structure (hfs) and the isotope shift (IS) of transitions between metastable levels of the configuration 4f
7 5d 6s and levels of the configuration 4f
6 5d 6s
2 of151Eu and153Eu were studied by means of the high resolution laser-atomic-beam technique. New data for the hfs in151Eu and153Eu were obtained as well as new and more accurate for the IS between151Eu and153Eu. The measured hfs constantsA andB of the 4f
6 5d 6s
2 configuration allow to perform a parametric analysis using the Sandars and Beck theory. The value of the Sternheimer correction is also disscused. 相似文献