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1.
Hyperfine structure and isotope shifts in five optical
transitions: 424.5 nm (
–
), 537.2 nm (
–
), 554.5 nm
(
–
), 560.9 nm
(
–
) and 666.0 nm
(
–
)
of Pb II have been measured. As a light source the discharge tube was used.
The hyperfine structure measurements were
performed using metallic isotope 207Pb. For isotope shifts
measurements natural lead was used. The high resolution spectral apparatus consisted of a silver
coated Fabry-Perot etalon and a grating spectrograph combined
with a CCD camera used as a detector. In the analysis of the
spectra a computer simulation technique was used. The hyperfine
structure observations yielded the splitting constants A for
seven levels of Pb II. The isotope shift studies enabled to
separate the mass and the field shifts and to determine values of
changes of the mean square nuclear charge radii. 相似文献
2.
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
3.
Zhi-Qing Zhang Zhen-Jun Xiao 《The European Physical Journal C - Particles and Fields》2009,59(1):49-66
We calculate the important next-to-leading-order (NLO) contributions to the B→KK
* decays from the vertex corrections, the quark loops, and the magnetic penguins in the perturbative QCD (pQCD) factorization
approach. The pQCD predictions for the CP-averaged branching ratios are
,
,
and Br(B
0→K
+
K
*−+K
−
K
*+)≈1.3×10−7, which agree well with both the experimental upper limits and the predictions based on the QCD factorization approach. Furthermore,
the CP violating asymmetries of the considered decay modes are also evaluated. The NLO pQCD predictions for
and
decays are
and
. 相似文献
4.
S. I. Tkachenko V. M. Romanova A. R. Mingaleev A. E. Ter-Oganesyan T. A. Shelkovenko S. A. Pikuz 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,54(2):335-341
Experimental results on electrical explosion of wires in vacuum with current density A/m2, current rise rate (dI/dt) ~ 50 A/ns and current pulse with amplitude ∼10 kA are presented. The structure of the discharge
channels in vacuum has been studied using laser shadow and schlieren imaging with 7 ns frames, UV pinhole images with 5 ns
frames and X pinch X-ray backlighting. The information on the dense core material and the conducting plasma distributions
was obtained in our experiments by analyzing and comparing the results obtained from all diagnostics. 相似文献
5.
H. Nowakowska M. Jasiński J. Mizeraczyk 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,54(2):511-518
We present results from simulations of 2D distributions of the electromagnetic field inside a waveguide-based axial-type microwave
plasma source (MPS) used for hydrogen production via methane reforming. The studies are aimed at optimization of discharge
processes and hydrogen production. We derive equations for determining electromagnetic field distributions and next determine
the electromagnetic field distributions for two cases – without and with plasma inside the MPS. For the first case, we examine
the influence of the length of the inner conductor of the coaxial line on electromagnetic field distributions. We have obtained
standing wave patterns along the coaxial line and found resonances for certain positions of the coaxial line inner conductor.
For the case with plasma inside the MPS, we perform calculations assuming that distributions of plasma parameters are known.
Simulations are done for several values of maximum electron density. We have found that for values of electron density greater
than strong skin effect in the plasma is observed. Consequently, plasma may be treated as an extension of the inner conductor
of the coaxial line. We have used FlexPDE software for the calculations. 相似文献
6.
Zhi-Gang Wang 《The European Physical Journal C - Particles and Fields》2009,61(2):321-329
We calculate the masses and the pole residues of the
heavy baryons Ω
c
0(css) and Ω
b
−(bss) with the QCD sum rules. The numerical values
GeV (or
GeV) and
GeV (or
GeV) are in good agreement with the experimental data. 相似文献
7.
P. D?m?t?r M. G. Benedict 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,53(2):237-242
We consider a quantum system consisting of N parts, each of which is a “quKit” described by a K dimensional Hilbert space.
We prove that in the symmetric subspace, , a pure state is not globally entangled, if and only if it is a coherent state. It is also shown that in the orthogonal complement
all states are globally entangled. 相似文献
8.
B. F. Parsons K. E. Strecker D. W. Chandler 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,38(1):15-20
In our previous work we investigated electronically non-adiabatic effects in
using crossed molecular beam scattering
coupled with velocity mapped ion imaging. The prior experiments placed
limits on the cross-section for electronically non-adiabatic spin-orbit
excitation
and electronically non-adiabatic spin-orbit
quenching
.
In the present work, we investigate
electronically non-adiabatic spin-orbit quenching for
which is the required first step for the
reaction of Cl* to produce ground state HCl+H products. In these
experiments we collide Cl (2P) with H2 at a series of fixed
collision energies using a crossed molecular beam machine with velocity
mapped ion imaging detection. Through an analysis of our ion images, we
determine the fraction of electronically adiabatic scattering in
Cl* +H2, which allows us to place limits on the cross-section for
electronically non-adiabatic scattering or quenching. We determine the following
quenching cross-sections σ quench(2.1 kcal/mol) = 26 ±
21 ?2, σ quench(4.0 kcal/mol) = 21 ±
49 ?2, and σ quench(5.6 kcal/mol) = 14 ±
41 ?2. 相似文献
9.
H.Q. Lu W. Fang Z.G. Huang P.Y. Ji 《The European Physical Journal C - Particles and Fields》2008,55(2):329-335
Quantum cosmology with a Born–Infeld (BI) type scalar field is considered. In the extreme limits of a small cosmological scale
factor the wave function of the universe can also be obtained by applying the methods developed by Hartle–Hawking (HH) and
Vilenkin. The HH wave function approach predicts that the most probable cosmological constant Λ equals ( equals the maximum of the kinetic energy of the scalar field). It is different from the original results (Λ=0) for the cosmological
constant obtained by Hartle–Hawking. The Vilenkin wave function predicts a nucleating universe with the largest possible cosmological
constant, and it is larger than 1/η. The conclusions can nicely be reconciled with cosmic inflation. We investigate the inflation
model with the BI type scalar field and find that η depends on the amplitude of the tensor perturbation δh, having the form
The vacuum energy in the inflation epoch depends on the tensor-to-scalar ratio δh/δΦ. The amplitude of the tensor perturbation δh may, in principle, be large enough to be discovered. However, it is only on the border of detectability in future experiments.
If it will have been observed in the future, this will be very interesting as regards determining the vacuum energy in the
inflation epoch.
PACS 98.80.Cq, 04.65.+e, 11.25.-w 相似文献
10.
A. Nadeem M. Nawaz S. U. Haq S. Shahzada M. A. Baig 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,53(2):147-151
We report term energies and quantum defects of highly excited even-parity states of mercury in the 83 876–84 140 cm-1 energy range, employing a two-step laser excitation scheme via the S0↦6s6p3P1 inter-combination transition. Two dye lasers, pumped by a common Nd:YAG laser, were frequency doubled by BBO crystals and
used to record the spectra in conjunction with a thermionic diode ion detector. Our new observations include the much extended
D2 (22 ≤n ≤52) series and a few members of the S1 (24 ≤n ≤30) Rydberg series. Members of the D2 Rydberg series with such a high n value are reported for the first time. The relative intensities of the D2 and S1 transitions (m = 4, 5 and 6) of group II-B elements excited from the P1 inter-combination states are also discussed. 相似文献
11.
A. Ehresmann W. Kielich L. Werner Ph. V. Demekhin D. V. Omel''yanenko V. L. Sukhorukov K.-H. Schartner H. Schmoranzer 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,45(2):235-246
Dispersed fluorescence from fragments formed after the de-excitation of the
1s-1π* resonances of N*O and NO* has been
measured in the spectral range of 118–142 nm. This range is dominated by
lines of atomic nitrogen and oxygen fragments and by the
bands in the NO+ ion which result from the participator Auger decay of the 1s-1π* resonances.
Ab-initio calculations of the transition probabilities between vibrational
levels during the reaction NO
N*O
⇒ NO
were used to explain the observed intensity dependence for the
fluorescence bands on the exciting-photon energy across
the resonances and on both v′ and v′′
vibrational quantum numbers. The multiplet structure of the 1s-1π* resonance and lifetime vibrational interference explain the observed exciting-photon energy dependence of the
fluorescence
intensity. A strong spin-orbit coupling between singlet and triplet states
of NO+ is proposed to reduce additional cascade population of the
state via radiative transitions from the
and
states and to explain
remaining differences between measured and calculated integral fluorescence
intensities. 相似文献
12.
The Lamb dip of CO rovibrational transition is detected by a room temperature extracavity RF optogalvanic cell and employed
to stabilize the frequency of a CO laser. The S/N ratio of optogalvanic signal is about 2000
at optical power < 1 W. The relative depth of Lamb dip is 2.3%. The S/N ratios of first and third harmonic demodulated saturation
signals are about 40
and 10
, respectively. The CO laser is stabilized using the first harmonic demodulated signal, and the frequency stability is better
than 300 kHz.
Concurrently, the influences of operational parameters, which include the coil current, partial pressures of gas mixture,
are investigated. A simple model for the influence of coil current is presented, and further improvements are addressed as
well. 相似文献
13.
I. D. Petrov V. L. Sukhorukov M. W. Ruf H. Hotop 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,53(3):289-302
Absolute photoionization cross sections for Ne atoms in the excited
levels (Paschen notation
) were calculated at near threshold energies within
the configuration interaction Pauli-Fock approach including core polarization.
The computed spectra and the lineshape parameters of the odd parity
2p1/2
5ns′/d′ autoionizing resonances are
found to be in good agreement with high resolution laser spectroscopic
results. Guided by the theoretical results, improved analyses of the measured
spectra by superimposed Fano-type profiles were achieved. Theoretical
predictions are presented for resonances which have not yet been studied
experimentally. In addition, we report the absolute partial photoionization
cross sections for the 2P3/2 and 2P1/2 channel at
photoelectron energies up to 7 eV. Except for the highest lying 2p1(1S0) level, these cross sections monotonically decrease with
energy (as reported earlier in single-electron calculations for the
Ne(2p53p) configuration) with branching ratios which essentially reflect
the core composition of the 2px levels. For the 2p1 level the resonance structure and the
partial cross sections are strongly influenced by a
Cooper-Seaton minimum in the d3/2
′ channel,located just above the 2P1/2 ionization limit. 相似文献
14.
The possible range of the η– mixing angle is determined from the transition form factors Fηγ(Q2) and with the help of up-to-date experimental data. For this purpose, the quark-flavor mixing scheme is adopted and the pseudoscalar
transition form factors are calculated in the framework of light-cone pQCD, in which the transverse-momentum corrections and
the contributions beyond the leading Fock state have been carefully taken into consideration. We construct a phenomenological
expression to estimate the contributions to the form factors beyond the leading Fock state, based on their asymptotic behavior
at Q2→0 and . By taking the quark-flavor mixing scheme, our results lead to , where the first error comes from the experimental uncertainty and the second error from the uncertainties of the parameters
of the wavefunction. The possible intrinsic charm component in η and is discussed, and our present analysis also disfavors a large intrinsic charm component in η and , e.g. .
PACS 13.40.Gp; 12.38.Bx; 14.40.Aq 相似文献
15.
Alexis Pokrovski 《Mathematical Physics, Analysis and Geometry》2007,10(3):197-203
Let be the spectrum of in L
2(ℝ), where q is an even almost-periodic complex-valued function with bounded primitive and derivative. It is known that , where is the spectrum of the unperturbed operator. Suppose that the asymptotic approximation to the first asymptotic correction
is given. We prove the formula that recovers the frequencies and the Fourier coefficients of q in terms of Δμ
n
.
相似文献
16.
F. Benedosso 《The European Physical Journal C - Particles and Fields》2007,49(1):61-64
We present measurements of azimuthal correlations between photons (from π0 decay) and charged hadrons in d+Au collisions at =200 GeV. We use di-hadron correlations to study parton fragmentation in d+Au collisions at RHIC. Specifically, the near-side
and away-side peaks of the azimuthal angular difference distribution are used to measure the root-mean-squared (RMS) fragmentation
transverse momentum and the mean intrinsic parton transverse momentum . The measurements with leading photons are compared to results using leading charged particles.
PACS 25.75.-q 相似文献
17.
R. M. Jennerich A. N. Keiser D. A. Tate 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,40(1):81-89
We have obtained Doppler-free spectra of transitions in the
→ 2p2(3P)
and
→
multiplets of atomic nitrogen using saturated absorption spectroscopy. These multiplets consist of
respectively of seven and eight transitions, and have center of gravity wavelengths of 821 nm and 869 nm. Values for the hyperfine
structure coupling constants of all the upper and lower states for these multiplets were obtained for both 14N and 15N. Isotope shifts of three transitions in each multiplet were also measured, and a significant J-dependence to the shifts
was observed. 相似文献
18.
F. P. Heßberger S. Hofmann D. Ackermann S. Antalic B. Kindler I. Kojouharov P. Kuusiniemi M. Leino B. Lommel R. Mann K. Nishio A. G. Popeko B. Sulignano S. Saro B. Streicher M. Venhart A. V. Yeremin 《The European Physical Journal A - Hadrons and Nuclei》2006,30(3):561-569
The decay of the isotopes 255Rf, 251No and 247Fm produced in the reactions
, and
was investigated by means of α-γ spectroscopy. Previously observed γ transitions in coincidence with α decays of 255Rf were confirmed, their energies and line intensities were measured more precisely, and their multipolarities were determined
as E1. In 251No a new isomeric state at E
* > 1700keV with a half-life of ≈ 2μs was identified. The decay of 247Fm was measured more precisely. A partial level scheme of the daughter nucleus 243Cf could be established. 相似文献
19.
S. H. Li C. Wang J. S. Liu X. X. Wang R. X. Li G. Q. Ni Z. Z. Xu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2005,34(1-3):215-218
Using time-of-flight spectrometry, the interaction of intense femtosecond
laser pulses with argon clusters has been studied by measuring the energy
and yield of emitted ions. With two different supersonic nozzles, the
dependence of average ion energy
on cluster size
in a large range of
has been measured. The experimental results indicate that
when the cluster size
, the average ion
energy
Coulomb explosion is the
dominant expansion mechanism. Beyond this size, the average ion energy gets
saturated gradually, the clusters exhibit a mixed Coulomb-hydrodynamic
expansion behavior. We also find that with the increasing gas backing
pressure, there is a maximum ion yield, the ion yield decreases as the gas
backing pressure is further increased. 相似文献
20.
Gouranga C. Nayak 《The European Physical Journal C - Particles and Fields》2009,59(3):715-722
We study the Schwinger mechanism for gluon-pair production in the presence of an arbitrary time-dependent chromo-electric
background field E
a
(t) with arbitrary color index a=1,2,…,8 in SU(3) by directly evaluating the path integral. We obtain an exact expression for the probability of non-perturbative
gluon-pair production per unit time per unit volume and per unit transverse momentum,
, from arbitrary E
a
(t). We show that the tadpole (or single-gluon) effective action does not contribute to the non-perturbative gluon-pair production
rate,
. We find that the exact result for non-perturbative gluon-pair production is independent of all the time derivatives
, where n=1,2,…,∞, and that it has the same functional dependence on the two Casimir invariants, [E
a
(t)E
a
(t)] and [d
abc
E
a
(t)E
b
(t)E
c
(t)]2, as the constant chromo-electric field E
a
result with the replacement: E
a
→E
a
(t). This result relies crucially on the validity of the shift conjecture, which has not yet been established. This result may
be relevant to the study of the production of a non-perturbative quark–gluon plasma at RHIC and LHC. 相似文献