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1.
W. Zhang S. You C. Sun Y. Zhang J. Xu Z. Ma Y. Feng H. Liu P. Quinet é. Biémont Z. Dai 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,53(1):1-8
First laser spectroscopic measurements of the 6s5d3D1-6s6p1P1 and 6s5d3D2-6s6p1P1 transitions in several isotopes of atomic barium have been performed. The hyperfine structure of these transitions was optically
resolved and isotope shifts for even and odd isotopes were determined. The isotope shifts show a deviation from their expected
behavior for odd isotopes in an analysis based on King-plots. This observation puts atomic structure calculations at test
because available theories do not predict this. A profound understanding of the wavefunctions for heavy alkaline earth systems
like barium (Ba) and radium (Ra) is essential for a theoretical evaluation of their sensitivity to fundamental symmetry breaking
effects such as they could be observed, e.g., through permanent electric dipole moments. Further the absolute frequency of
the 6s2
1S0-6s6p3P1 intercombination line in 138Ba was determined to be 12 636.6232(1) cm-1. 相似文献
2.
I. Sakho A. S. Ndao M. Biaye A. Wague 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,47(1):37-44
Screening Constant by Unit Nuclear Charge (SCUNC) is a new analytical method
suitable for the treatment of the properties of He-like systems. In this
paper, the possibilities of the method are demonstrated for calculating in
the framework of semi-empirical procedure, total energies, total
electron-electron interaction energies and excitation energies for
(ns2)1Se, (np2)1De and (Nsnp)1P° doubly
excited states of He-like ions. The proposed semi-empirical scheme,
leads to accurate results in good agreement as well as with available other
theoretical results than experimental data. 相似文献
3.
S. Kröger I. K. Öztürk F. G. Acar G. C. Başar G. Başar J.-F. Wyart 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(1):61-70
A parametric analysis of the fine and the magnetic dipole hyperfine structure
for the three configurations of odd parity 4d35s5p, 4d45p and
4d25s25p was performed.
Effective one-electron parameters were determined and
theoretical predictions are given for the magnetic dipole
hyperfine structure constants A
for the levels of these three configurations.
Additionally,
12 new energy levels could be found, four of odd and eight of even parity,
by re-analysing data for experimental wavelengths of Nb. 相似文献
4.
D. Ashkenasi S. Kröger H.-D. Kronfeldt 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,11(2):197-205
The isotope shift (IS) and hyperfine structure (hfs) of nine levels (31720 to 38921 cm-1) assigned to the configuration 4
f
12
6
s
7
s in neutral erbium have been determined experimentally using Doppler-reduced saturation absorption spectroscopy in a gas discharge.
We performed a fine structure analysis in the SL-coupling scheme of the single configuration 4
f
12
6
s
7
s, confirming and extending the classification of even parity Er I levels. We discriminated the different hfs contributions
of the 4f12 core and the (6
s
+7
s) outer electrons of the shell in a non-relativistic JJ-coupling approach and in the relativistic effective tensor operator formalism in SL-coupling. The relativistic one-electron parameters of the hfs for 167Er were fitted to the experimental data by a least squares fit procedure: [0pt] a
01
4f
=-147(3) MHz, [0pt] a
10
6s
+
a
10
7s
=-1840(30) MHz, [0pt] b
02
4f
=6560(80) MHz. The level dependencies of the isotope shift were evaluated based on crossed second order (CSO) effects. We obtained
the following results for the CSO parameters for the isotope pairs 170-168Er: d
6s7s
=-740(30) MHz, z
4f
= 0(5) MHz, (
g
3,6s
(
f
, 6
s
)+
g
3, 7s
(
f
, 7
s
))= -24(15) MHz and for 170-166Er: d
6s7s
=-1500(50) MHz, z
4f
=0(10) MHz, (
g
3,6s
(
f
,6
s
)+
g
3,7s
(
f
+7
s
))=-50(29) MHz. The resulting parameters for the hfs are compared with those known for other configurations of the Er atom and ion.
Received 16 May 1999 and Received in final form 31 January 2000 相似文献
5.
Sonjoy Majumder B. K. Sahoo R. K. Chaudhuri B. P. Das D. Mukherjee 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(3):441-445
Ab initio calculations have been carried out to study the magnetic dipole and
electric quadrupole hyperfine structure constants of 205Pb+. Many-body
effects have been considered to all orders using the relativistic coupled-cluster theory in the singles, doubles and partial
triples approximation. The trends of these
effects are found to be different from atomic systems that have been studied
earlier. 相似文献
6.
J. Mitroy J. Y. Zhang M. W. J. Bromley K. G. Rollin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,53(1):15-19
The blackbody radiation shift of the Al+ 3s2
1Se
0 ↦ 3s3p 3P○
0 clock transition is evaluated. The polarizabilities of the two states are determined by means of configuration interaction
calculations in conjunction with oscillator strength sum rules. The ground state polarizability was 24.14 ±0.12 a.u. while
the metastable state polarizability was 24.62 ±0.25 a.u. The derived frequency shift at 300 K was Δν= -0.0042 ±0.0032 Hz.
Some auxiliary sum rules are evaluated that allow for the conversion of a finite frequency polarizability difference to a
static polarizability difference. 相似文献
7.
J. P. Marques F. Parente P. Indelicato 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(3):457-465
In this paper, we used the multiconfiguration Dirac-Fock method to compute with high precision the influence of the hyperfine
interaction on the [Ar]
P0 level lifetime in Zn-like ions for stable and some quasi-stable isotopes of nonzero nuclear spin between Z=30 and Z=92. The
influence of this interaction on the
[Ar]
P
P0 separation energy is also calculated for the same ions. 相似文献
8.
T. J. Wasowicz 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,53(3):263-272
Isotope shifts in the 623.7 nm line of Pb I have been measured. Then, in a spectral range of nm the optical isotope shifts in 24 lines of neutral and singly ionized lead have been analyzed using a combined model-independent
method. From the combination of the optical isotope shifts data with elastic electron scattering, muonic X-ray and electronic
Kα X-ray data, we were able to determine the two contributions to the total isotope shift, namely the mass and the
field shifts, and to obtain the values of several nuclear factors for a long chain of lead isotopes. 相似文献
9.
J. Lecointre D. S. Belic J. J. Jureta R. Janev P. Defrance 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,50(3):265-278
Absolute cross sections for electron-impact dissociative excitation and
ionization of CD+
4 leading to formation of ionic products (CD2+
4, CD+
3, CD+
2, CD+, C+, D+
3, D+
2, and D+) have been measured. The animated crossed-beams
method is applied in the energy range from the reaction threshold up to 2.5 keV. Around 100 eV, the maximum cross sections
are found to be (3.8±0.2) ×10-19 cm2,
cm2,
(7.1±0.8) ×10-17 cm2, (9.0±0.8) ×
10-17 cm2 and (3.7±0.4) ×10-17 cm2 for the
heavy carbonaceous ions CD2+
4, CD+
3, CD+
2, CD+ and C+ respectively. For the light fragments, D+
3, D+
2, and D+, the cross sections around the maximum are
found to be (5.0±0.6) ×10-19 cm2, (1.7±
0.2) ×10-17 cm2 and (10.6±1.0) ×10-17 cm2, respectively. The cross sections are presented in closed analytic
forms convenient for implementation in plasma simulation codes. The analysis
of ionic product velocity distributions allows determination of the kinetic
energy release distributions which are seen to extend from 0 to 9 eV for
heavy fragments, and up to 14 eV for light ones. The comparison of present
energy thresholds and kinetic energy release with available published data
gives information about states contributing to the observed processes.
Individual contributions for dissociative excitation and dissociative
ionization are determined for each detected product. A complete database
including cross sections and energies is compiled for use in fusion
application. 相似文献
10.
M. A. Baig 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(3):437-442
We report new high resolution photoabsorption measurements of the
5d-subshell excitation spectra of mercury using a 3-meter normal incidence
spectrograph equipped with a 6000 line/mm holographic grating and
synchrotron radiation emitted by the Bonn 2.5 GeV electron accelerator as
the background source of continuum. The observed spectra reveal autoionizing
resonances attached to the 5d9(2D5/2)6s2 and
5d9(2D3/2)6s2 parent ion levels of mercury. We have
analysed the line shapes of the lower members of the 5d96s2 np and
nf J = 1 autoionizing resonances using the phase shifted formulation of the
MQDT and extracted the interaction parameters. 相似文献
11.
A. Dilip I. Endo A. Fukumi M. Iinuma T. Kondo T. Takahashi 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,14(3):271-277
The excitation energies and hyper-fine structure constants of the low-lying levels of Sm atom are calculated using the multi-configuration
Dirac-Fock (MCDF) method. The results show that the excitation energies of the ground state multiplets can be calculated accurately
using a small orbital set but the higher levels need larger orbital sets. Similar inference can also be drawn from the discrepancy
between the calculated values of the hyper-fine constants and the experimental data. A sequence of MCDF calculation demonstrates
the effect of the MCDF potential on the orbitals. Among the rare earth atoms Sm is a promising candidate for discrete symmetry
violation experiments in atoms. This makes accurate theoretical calculations necessary since parameters in particle physics
can be derived by combining the experimental results with the theoretical results. And these could be a probe for the physics
beyond the standard model.
Received 10 October 2000 and Received in final form 23 January 2001 相似文献
12.
X. H. Ren J. T. Zhang Y. Wang Z. Z. Xu D. S. Guo 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,51(3):401-407
We study the photoelectron angular distributions (PADs) of diatomic molecule
H2
+ irradiated by intense laser fields using a nonperturbative
scattering theory. We find that the internuclear vector may change the PADs.
The PADs have qualitative changes with the increasing of the internuclear
distance. The molecular orientation affect the symmetry of the PADs. When the
internuclear vector is vertical or parallel to the laser polarization vector,
the PADs are four-fold symmetric; for other case the PADs are two-fold
symmetric. Due to the modulation effect resulting from the molecular
multi-core nature, the size of the jet and the main lobe can be enlarged or
reduced. The molecular modulation effect become obvious for large
internuclear distance. 相似文献
13.
P.?Mas?owski K.?Bielska A.?Cygan J.?Domys?awska D.?Lisak R.?Ciury?o A.?Bielski R. S.?Trawiński 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,51(3):295-302
Careful analysis of the intercombination 51S0–53P1 line of the 113Cd isotope with two hfs components
and was carried out.
The hyperfine splitting of this line was determined to uncertainty less than
10-3 cm-1 using neon-perturbed Doppler limited spectra. 相似文献
14.
Dr. Minakshi L. K. Jha S. N. Chatterjee B. N. Roy 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,51(3):331-339
H+ and He2+ impact single and double ionization cross
sections of ground state lead atoms have been calculated in the binary
encounter approximation. Calculations of direct double ionization cross
sections have been performed in the modified double binary encounter model.
The accurate expressions of σΔE (cross-section for energy
transfer ΔE) and Hartree-Fock velocity distributions for the target
electrons have been used throughout the calculations. Contributions to
double ionization from Auger effect following ionization of inner shells
have been considered in the present work. Our H+ impact single and
double ionization cross sections are in good agreement with the experimental
observations. In calculations of He2+ impact cross sections, the
present theoretical approach shows limited success in the experimentally
investigated region (50–350 keV amu-1). 相似文献
15.
A. M. Frolov D. M. Wardlaw 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,50(1):9-12
Analytical formulas are derived for the Z-1 (Q-1) expansions of the total energies in the two-, three- and four-electron atomic systems. The coefficients in these formulas
are determined from the results of accurate and highly accurate computations with correlated wave functions. The accuracy
of our formulas is sufficient to evaluate the total ground state energy of an arbitrary non-relativistic ion with two, three
and four electrons. 相似文献
16.
The absorption spectra, fluorescence spectrum and fluorescence decay curve of Nd3+ ions in CaNb2O6 crystal were measured at room temperature. The peak absorption cross section was calculated to be 6.202×10−20 cm2 with a broad FWHM of 7 nm at 808 nm for E//a light polarization. The spectroscopic parameters of Nd3+ ions in CaNb2O6 crystal have been investigated based on Judd-Ofelt theory. The parameters of the line strengths Ω
t
are Ω
2=5.321×10−20 cm2,Ω
4=1.734×10−20 cm2,Ω
6=2.889×10−20 cm2. The radiative lifetime, the fluorescence lifetime and the quantum efficiency are 167 μs, 152 μs and 91%, respectively. The fluorescence branch ratios are calculated to be β
1=36.03%,β
2=52.29%,β
3=11.15%,β
4=0.533%. The emission cross section at 1062 nm is 9.87×10−20 cm2. 相似文献
17.
K. Koc 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,53(1):9-14
Lifetime of 2s22p 2P3/2 level along with fine structure separations for the lowest 2P doublet of boron-like ions, from Z=14 to Z=30 have been calculated using multireference relativistic configuration interaction
(MR RCI) method based on the no-pair Dirac-Coulomb-Breit (DCB) Hamiltonian. Analytic basis sets of Gaussian-type functions
are employed to expand the upper and lower components of the Dirac four-spinors in the matrix Dirac-Fock self-consistent field
(DF SCF) and relativistic MR CI procedures. Error with respect to variation of basis set parameters was estimated. QED corrections
were estimated by evaluation of electron self-energy and vacuum polarisation. 相似文献
18.
M. Sabidó J. de Andrés J. Sogas J. M. Lucas M. Albertí J. M. Bofill I. Rabadán A. Aguilar 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,47(1):63-70
The dynamics of collisional processes between Mg atoms and caesium ions is studied using the hemiquantal (HQ) approach with
special attention to the collisional channels leading to Mg(3 1P) and Cs(6 2P) states, for which the corresponding emission excitation functions have been previously measured in our laboratory. The
radial and angular non-adiabatic couplings between the manifold of quasimolecular states have been determined using an ab
initio configuration interaction calculation. The cross-sections for the different channels, as a function of the laboratory
collisional energy, are compared with experimental values. The dynamical calculations indicate that, for the inelastic processes
considered, the range of relevant impact parameters is small, active collisions being of the head-on type.
. 相似文献
19.
S. Gao G. C. Yang S. L. Lin M. L. Du 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(2):189-196
Photo-detached electrons of negative hydrogen ion in
parallel electric and magnetic fields show quite complicated classical
dynamical behavior, and a sequence of bifurcation and anti-bifurcation
occurs. We investigate the effects of bifurcations on the flux distribution
of photo-detached electrons by using position and momentum diagrams.
Detached-electron flux distributions are calculated based on a uniform
semi-classical theory. The flux distributions exhibit patterns with multiple
rings. The bright rings correspond to special points in the diagrams. The
flux distributions can be controlled by adjusting the magnetic field
strength while fixing the electric field. 相似文献
20.
S.I. Themelis Y. Komninos C.A. Nicolaides 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(3):277-293
This paper discusses theory and results on 1P0 doubly excited states (DES) in He and in H- of very high excitation, up to the N
= 25 manifold. Our calculations employed full configuration interaction (CI) with large hydrogenic basis sets and produced correlated
wavefunctions for the four lowest roots at each hydrogenic manifold by excluding open channels and the small contribution
of series belonging to lower thresholds. The suitability of the hydrogenic basis sets for such calculations is justified,
apart from their practicality, by the fact that, by computing from them natural orbitals, the results were shown to be the
same with those of earlier multiconfigurational Hartree-Fock (MCHF) calculations on low-lying DES. In total, 160 states were
computed, most of them for the first time. Their energy spectrum should be of use to possible future photoabsorption experiments.
For certain low-lying DES up to N
= 13, for which previous reliable results are available, comparison of the calculated energies shows good agreement. The correlated
wavefunctions contain systematically chosen single and double excitations from each hydrogenic manifold of interest. From
their analysis, we determined the “goodness" of different quantum numbers and the geometry (average angles and radii) as a
function of excitation. For the Sinano lu-Herrick (
K
,
T
) classification scheme, whose basis is a restricted CI with hydrogenic functions and which has thus far been tested only on
low-lying DES, we established that, whereas T remains a good index as energy increases, K does not. Consequently, a more flexible than K quantum number is needed in order to account for most of the additional correlation. This number, represented by F
=
N
-
K
- 1, where N and K are not good numbers anymore, produces consistently a much higher degree of purity than the (
K
,
T
) scheme does, especially as N increases and as the relative significance of various virtual excitations due to electron correlation increases. Among the
four states of each manifold, in all cases in H- and in most cases in He, the three are of the intrashell type and one is of the intershell type with (
F
,
T
) = (0, 0). The lowest intrashell states and the lowest intershell states exhibit a wide angle geometry tending to 180
°
as N
↦∞.
Received 10 September 2001 and Received in final form 12 November 2001 相似文献