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1.
B. Zmerli N. Ben Nessib M. S. Dimitrijević 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,48(3):389-395
We investigated here temperature dependence of Stark
widths for neutral atom spectral lines in order to find a more
precise method for scaling with temperature than sometimes used
dependence T-1/2, which is often inadequate particularly for
Stark broadening of neutral emitter lines. We found here an
analytical scaling with temperature within simplified
semiclassical approaches of Freudenstein and Cooper and
Dimitrijević and Konjević. For analysis of the temperature
dependence, lines of HeI were used. 相似文献
2.
K. J. Öberg 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(1):25-47
Transition isotope shifts of 3s–3p transitions in Ne II and Ne III are measured in Fourier transform spectra from a hollow-cathode
source. Accurate absolute line-center positions of the 20Ne isotope are derived for the purpose of tertiary wavelength standards in the region 2000–5000 ?. A robust statistical treatment
is applied, yielding line-position uncertainties that are lower than for the Ar II secondary standards used as references.
The influence of Stark shifts on both the new Ne II standards and the Ar II standards is also investigated. In addition, improved
wavenumbers of the 3p–3d and 3p–4s transitions are presented, of which 12 in Ne II have been measured for the first time.
Electronic supplementary material Supplementary Online Material 相似文献
3.
C. Stehlé D. Gilles A.V. Demura 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,12(2):355-367
The theoretical basis is presented that allows to compute the Stark broadened line shapes of atomic ions up to the quadrupole
terms in the interaction potential between the radiator and the plasma electric microfields and their gradients. The nature
of the corrections due to the plasma polarization effects associated with the electron distribution around ion perturbers are carefully analyzed. The relevant universal plasma functions are evaluated in a cluster expansion or by Monte Carlo simulations,
and the line shape is calculated with ion dynamic effects by the Model Microfield Method. The asymmetry of the Lyman line of hydrogenic ions is then studied.
Received 21 January 2000 and Received in final form 27 April 2000 相似文献
4.
N. F. Allard J. F. Kielkopf F. Allard 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(3):507-514
Spectral line widths of the light alkalies are presented for
conditions prevailing in brown dwarf atmospheres. A unified line shape theory
and a set of pseudopotentials are used to compute
widths of Li, Na, and K resonance lines perturbed by He and H2.
While limited available experimental data
confirm the trends found in the theoretical values reported here,
they suggest that improved potentials are needed. 相似文献
5.
A. Calisti L. A. Bureyeva V. S. Lisitsa D. Shuvaev B. Talin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(3):387-392
A study of hydrogen lines emitted in dense and low
temperature plasmas is presented. Coupling and ionization effects in a
transition from impact to quasi-static broadening for electrons are analyzed with the help of the Frequency Fluctuation Model
(FFM). Electron broadening of Balmer series lines is studied for different densities and temperatures spanning a wide domain
from impact to quasi-static limit. It is shown that electronic broadening makes a transition from impact to quasi-static limit
depending on plasma conditions and principal quantum number. Even for the
Balmer alpha line, at a density equals 1018 cm-3 and a temperature equals 1 eV, this transition occurs both in the wings and the core of the line. 相似文献
6.
S. Porikli D. Demir Y. Kurucu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,47(3):315-323
In this work, the effects caused by different chemical combination and external magnetic field in several copper and zinc
compounds (Cu, CuBr, Cu2O, CuI, CuCl, Cu2Te, Cu5Si, CuSO4, CuSeO4.5H2O, CuCl2, Cu(NO3)2, CuS, CuSe, CuF2, CuF2.3H2O, CuBr2, Cu(ClO4)2.6H2O, Zn, ZnSO4.5H2O, Zn(C2H3O2)2, ZnF2, Zn(NO3)2.6H2O, ZnO, ZnS, ZnSe, ZnTe and ZnF2.4H2O) were studied using a Si(Li) detector. The samples were excited by 22.69 keV X-rays from 109Cd point radioactive source of strength 10 mCi in the external magnetic field of intensities 0.6 T and 1.2 T. The shift, asymmetry,
FWHM and Kβ/Kα intensity ratio values were determined. For B = 0, the present experimental results were compared with the
experimental and theoretical data in literature. The results have shown that the atomic parameters such as energy shifts,
asymmetry indices, FWHM and Kβ/Kα intensity ratios can change when irradiation is conducted in a magnetic field. 相似文献
7.
E. Vliegen P. A. Limacher F. Merkt 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,40(1):73-80
The full three-dimensional velocity distributions of decelerated and accelerated particles in a Stark decelerator for Rydberg
atoms and molecules have been
measured. In the experiment, argon atoms in a supersonic beam are excited to low-field and high-field seeking Stark states
with principal quantum number in the range n=15 to 25 and are decelerated in a 3 mm long decelerator consisting of four electrodes
on which time-dependent voltages are
applied. The time dependence of the resulting inhomogeneous electric field is chosen such that the decelerating force acting
on the high-field seeking states is maximized
at each point along the trajectories. The three-dimensional velocity distribution of the atoms before and after the deceleration
is determined by measuring
times of flight and two-dimensional images of the atomic cloud on the detector.
Under optimal deceleration conditions, the decrease in kinetic energy in the longitudinal dimension amounts to 1.0×10-21 J and the increase in mean kinetic
energy in the transverse dimensions is only 1.0×10-23 J. The corresponding temperatures of 100 mK and 300 mK in the two transverse dimensions are sufficiently
low that trapping can be envisaged. The possibility of focusing a Rydberg atom beam is demonstrated experimentally. 相似文献
8.
B. Friedrich 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,38(1):209-214
We present a simple analytic approximation for evaluating the
ensemble-averaged orientation or alignment of a beam of molecules subjected
to a strong static or radiative field. This approximation is based on the
eigenproperties which polar or polarizable molecules exhibit in the
strong-field, harmonic-librator limit, and on the Boltzmann statistics of
the free rotor states which adiabatically correlate with the harmonic
librator states. For either the permanent or induced dipole case, the
resultant formula involves just two dimensionless parameters which
characterize the strength of the molecule-field interaction and the
rotational temperature. The net polarization of a molecular beam thus
obtained is shown to be in an excellent agreement with the exact values
computed numerically from first principles. The validity range of the
approximation includes the large-interaction, high temperature regions of
the parameter space where first-principle calculations are onerous. 相似文献
9.
F. S. Krasniqi O. Renner E. Dalimier E. Dufour R. Schott E. Förster 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,39(3):439-444
A systematic study of the Langmuir-wave-caused dips (L
dips) observed in profiles of the Al Ly γ line emitted from
laser irradiated sandwich targets indicates that these fine
spectral features can be used as a tool for density diagnostics in
intermediately coupled plasmas. The spectroscopic data required
for a reliable identification of L dips were collected by a
vertical-geometry Johann spectrometer providing high spectral and
spatial resolution. The electron densities deduced from the
evolution of the L dips along the laser target axis compare well
with those derived from hydrosimulations and from measurements of
the line widths and shifts. 相似文献
10.
J. Halenka W. Olchawa 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(3):425-433
A method of calculation of inhomogeneity microfield tensors in Debye plasma,
using the Mayer-Mayer cluster expansion, is presented.
The octupole inhomogeneity tensor of the ion microfield at a neutral
emitter has been calculated for the first time.
The quadrupole inhomogeneity tensor of the ion microfield at a neutral
emitter has been recalculated.
We have performed numerical calculations for plasma consisting of atoms, electrons
and singly or doubly charged ions. 相似文献
11.
R. Ashby J.J. Clarke W.A. van Wijngaarden 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(3):327-331
6Li 32D
3/2, 5/2
states were studied using a diode laser to first excite the 2P
3/2
state and a dye laser to populate the 32D
3/2, 5/2
states. The dye laser was modulated by an electro-optic modulator and intersected an atomic beam that passed through a field
free region and subsequently through a uniform electric field. A value of 1084.24±0.20 MHz was found for the 32D fine structure splitting. The scalar and tensor polarizabilities were determined to be α
(3D
3/2
) = - 3.753±0.015, α
2
(3D
3/2
) = 2.893±0.017, α
(3D
5/2
) = - 3.772±0.008 and α
2
(3D
5/2
) = 4.058±0.013 MHz/(kV/cm)2.
Received 26 September 2002 / Received in final form 22 January 2003 Published online 11 March 2003
RID="a"
ID="a"e-mail: wlaser@yorku.ca 相似文献
12.
M.A. Mejri H. Nguyen Z. Ben Lakhdar 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,4(1):125-129
This paper is concerned with lineshifts of hydrogen-like ions due to electron collisions in dense and hot plasmas. These collisions
are treated by including all effects due to monopole, dipole, and quadrupole interactions between radiator and electron perturbers.
The latter follow exact hyperbolic trajectories with a possible penetrating part inside atomic orbits. A simple closed form
for the line shift has been derived. Comparison between our semi-classical results and the quantum mechanical ones shows good
agreement for a large range of high electron densities and temperatures.
Received: 30 June 1997 / Revised: 28 April 1998 / Accepted: 29 April 1998 相似文献
13.
W. F. Mahmoudi N. Ben Nessib S. Sahal-Bréchot 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,47(1):7-10
Owing to the increasing sensitivity of detectors,
accurate line profiles are needed for accurate stellar
atmospheres modelling and for laboratory and technological plasmas
as well. So, Stark broadening parameters of isolated lines of
complex atoms and ions within the impact and quasistatic
approximation are needed, even if the atomic abundance of the considered element is low.
Angular factors of the diagonal line strength entering the
quadrupole term appearing in the semi-classical expression of the
width of line broadened by electron or ion perturbers, are needed.
The aim of this paper is to extend the previous calculations of
this diagonal multiplet factor which were obtained for
configurations of the type ln and l1
nl2
m to
more complex configurations in LS coupling.
To study the Stark broadening of isolated lines in the impact and
quasistatic approximation, we use the semi-classical-perturbation
treatment, including both dipole and quadrupole contribution in
the expansion of the electrostatic interaction between the optical
electron and the perturber. We also use the Fano-Racah algebra.
Angular factors of the diagonal line strength entering the
quadrupole term appearing in the semi-classical expression of the
width of line broadened by electron or ion perturbers, are
calculated. New diagonal multiplet factor formulae for more
complicated configurations such as
(n1l1
n(LnSn)n2l2
m(LmSm)n3l3
p(LpSp))
are provided.
These formulae can enter the computer Stark semi-classical
perturbation codes. 相似文献
14.
M. A. Gigosos M. Á. González N. Konjević 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,40(1):57-63
We report results of the Stark broadening calculations for Sr+ and
Ba+ resonance lines in ultracold plasmas using semiempirical formulas
and numerical computer simulation technique. The simulation results show
that strong collisions dominate Stark broadening at very low electron
temperatures and weak collision approximation used recently by Vrinceanu
et al. cannot be applied in this temperature region. Consequently, the
temperature trend of Stark widths and shifts changes from
successfully used at elevated temperatures to an increasing trend
with temperature, which is characteristic for strong collisions at
low temperature. 相似文献
15.
H. M. Gao S. L. Ma C. M. Xu L. Wu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,47(2):191-196
Electron densities in an atmospheric helium arc plasma have been measured with the Stark broadening parameters of helium spectral
lines. The spatially distributed radiation intensities are converted to plasma emission coefficients at every wavelength by
means of Abel inversion. From the inverted profiles of He I lines of 4713 ?, 5016 ?, and 6678 ? electron density has been
calculated, which ranges from 0.5 ×1016 to 4 ×1016 cm-3 for a helium arc with current 200 A. Stark widths of He I lines of 3889 ? and 7065 ? are determined based on the measurements
and compared with existing data. 相似文献
16.
V. Milosavljević S. Djeniže 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,15(1):99-104
Characteristics of the Stark broadened and overlapping 447.1 nm He I spectral line and its forbidden 447.0 nm components have
been measured at electron densities between 4.4×1022 m-3 and 8.2×1022 m-3 and electron temperatures between 18 000 K and 33 000 K in plasmas created in five various discharge conditions using the
low pressure pulsed arc as an optically thin plasma source operated in helium-nitrogen-oxygen gas mixture. Good agreement
was found among our measured line characteristics and their existing calculated values, based on the quasistatic approximation.
Possible influence of the singly ionized oxygen impurity atoms (O II) on the intensity values of the dip between allowed and
forbidden components was found that can explain the disagreement among some existing experimental and calculated line characteristics
data, at higher electron temperatures and densities. On the basis of the observed asymmetry of the 447.1 nm spectral line
profile we have obtained the ion contribution parameter at 1022 m-3 electron density and 8 000 K electron temperature.
Received 20 February 2001 and Received in final form 25 April 2001 相似文献
17.
B. Brunetti P. Candori S. Falcinelli B. Lescop G. Liuti F. Pirani F. Vecchiocattivi 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,38(1):21-27
A crossed beam experiment is carried out to measure the energy of electrons
emitted in Penning ionization processes by Ne*(3P2,0)–Kr
collisions. The electron energy spectra have been measured at four different
collision energies: 0.050, 0.140, 0.190, 0.460 eV. The analysis of the
results allows the separation of spin orbit contributions both in the
entrance and in the exit channels providing the related cross-section
ratios. Some theoretical considerations have been made to clarify nature and
role of interatomic potentials driving the collisions and some general
features about the role of atomic fine structure in the Penning ionization
processes. 相似文献
18.
I. Baumann A. Breidenassel C. Zühlke A. Kasimov G. zu Putlitz I. Reinhard K. Jungmann 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,12(1):117-122
The pressure shifts of the 3s4s3S P0,1,2 transition of magnesium atoms immersed in superfluid helium have been measured at K between saturated vapour pressure and 24 bar. The wavelength is blue shifted linearly by . This value can be satisfactorily described in the framework of the standard bubble model.
Received 18 February 2000 相似文献
19.
G. Marx G. Tommaseo G. Werth 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,4(3):279-284
Laser-microwave double and triple resonance experiments were performed on clouds of Ba+ ions confined in a Penning ion trap to induce and detect electronic and nuclear spin flip transitions. Collisions with buffer
gas molecules in the trap was used to reduce the lifetime of a long lived metastable state of the ions, in which population
trapping might occur, and to cool the ions to the ambient temperature. Loss of ions from the trap by collisions were prevented
by coupling the magnetron and reduced cyclotron motions by an additional r.f. field at the sum frequency of the two motions.
Electronic Zeeman transitions in 138Ba+ and 135Ba+ were observed at a full width of about 3 kHz at a transition frequency of 80 GHz. The uncertainty of the line center was
. From the magnetic field calibration by the cyclotron resonance of electrons stored in the same trap the gJ-factor for both isotopes could be determined to . From radiofrequency induced transitions of 135Ba+ the nuclear g-factor could be determined . Both measurements improve earlier results by about one order of magnitude.
Received: 9 July 1998 / Accepted: 14 July 1998 相似文献
20.
Y. Marandet H. Capes L. Godbert-Mouret M. Koubiti J. Rosato R. Stamm 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,39(2):247-260
In this work we investigate the influence of low
frequency turbulence on Doppler spectral line shapes in magnetized
plasmas. Low frequency refers here to fluctuations whose typical
time scale is much larger than those characterizing the atomic
processes, such as radiative decay, collisions and charge exchange.
This ordering is in particular relevant for drift wave turbulence,
ubiquitous in edge plasmas of fusion devices. Turbulent fluctuations
are found to affect line shapes through both the spatial and time
averages introduced by the measurement process. The profile is
expressed in terms of the fluid fields describing the plasma.
Assuming the spectrometer acquisition time to be much larger than
the turbulent time scale, an ordering generally fulfilled in
experiments, allows to develop a statistical formalism. We proceed
by successively investigating the effects of density, fluid velocity
and temperature fluctuations on the Doppler profile of a spectral
line emitted by a charge exchange population of neutrals. Line
shapes, and especially line wings are found to be affected by ion
temperature or fluid velocity fluctuations, and can in some cases
exhibit a power-law behavior. These effects are shown to be
measurable with existing techniques, and their interpretation in
each particular case would rely on already existing tools. From a
fundamental point of view, this study gives some insights in the
appearance of non-Boltzmann statistics, such as Lévy statistics,
when dealing with averaged experimental data. 相似文献