共查询到20条相似文献,搜索用时 421 毫秒
1.
Recently, we have reported photoassociation of laser-cooled Rb and Cs atoms, decay of the RbCs photoassociation resonances
to high levels of the
state, and reexcitation to vibronic levels of the
state [Kerman et al. , Phys. Rev. Lett. 92, 033004; 153001 (2004)]. Considering the reexcitation spectrum, we report here a preliminary analysis of perturbations in
the c state by high levels of the
and low levels of the
state. Mixing with the B state provides the singlet character needed to stimulate decay to v = 0 of the
ground state. We conclude that an experimental procedure that involves photoassociation of laser-cooled atoms, radiative
decay, and stimulated Raman transfer to the ground electronic state is a feasible method for producing translationally, rotationally,
vibrationally and electronically cold RbCs molecules.
Electronic supplementary material to this article is available at and is accessible for authorized users.
Received: 1 September 2004, Published online: 23 November 2004
PACS:
33.80.Ps Optical cooling of molecules; trapping - 34.50.Gb Electronic excitation and ionization of molecules; intermediate
molecular states (including lifetimes, state mixing, etc.) - 33.20.Kf Visible spectra - 34.20.-b Interatomic and intermolecular
potentials and forces, potential energy surfaces for collisions - 33.15.Pw Fine and hyperfine structure
A supplementary table (Tab. I) is only available in electronic form at http: //www.eurphysj.org 相似文献
2.
The ground state X
of NaCs was studied by laser induced fluorescence Fourier-transform spectroscopy. An accurate potential energy curve was
derived from more than 5000 transitions. This potential reproduces the experimental observations within their uncertainties
of
cm-1 and covers about 99.97% of the potential well depth. Few vibrational levels of the shallow state a
below the atomic ground state asymptote were observed. The identification is mainly done by the observed and quantitatively
interpreted molecular hyperfine structure applying atomic parameters of the ground states of Na and Cs. An estimated potential
curve for a
is reported which can be used together with that of X
for coupled channel calculations of cold collisions between Na and Cs. An example is given.
Electronic supplementary material to this article is available at and is accessible for authorized users.
Received: 10 September 2004, Published online: 23 November 2004
PACS:
31.50.Bc Potential energy surfaces for ground electronic states - 33.20.Kf Visible spectra - 33.20.Vq Vibration-rotation analysis
- 33.50.Dq Fluorescence and phosphorescence spectra
Supplementary tables (Tabs. I-III) are only available in electronic form at http: //www.eurphysj.org 相似文献
3.
Zhi-Gang Wang Wei-Min Yang Shao-Long Wan 《The European Physical Journal C - Particles and Fields》2004,37(2):223-231
Making the assumption of explicit isospin violation arising from f
0(980)-a
0(980) mixing, we take the point of view that the scalar mesons f
0(980) and a
0(980) have both strange and non-strange quark-antiquark components and evaluate the strong coupling constants
within the framework of the light-cone QCD sum rules approach. The large strong scalar-KK couplings through both the
and
components
,
,
and
will support the hadronic dressing mechanism; furthermore, in spite of the constituent structure differences between the f
0(980) and a
0(980) mesons, the strange components have larger strong coupling constants with the K
+
K
- state than the corresponding non-strange ones,
and
. From the existing controversial values, we cannot reach a general consensus on the strong coupling constants
and the mixing angles.Received: 9 January 2004, Revised: 23 July 2004, Published online: 2 September 2004 相似文献
4.
In the context of the littlest Higgs (LH) model, we study the process
. We find that the new gauge bosons Z
H
and B
H
can produce significant correction effects on this process, which can be further enhanced by suitably polarized beams. In most of the parameter space preferred by the electroweak precision data, the absolute value of the relative correction parameter
is larger than 5 %. As long as
and
the absolute value of the relative correction parameter
is larger than
. With reasonable values of the parameters of the LH model, the possible signals of the new gauge bosons B
H
and Z
H
can be detected via the process
in the future LC experiments with the CM energy
. B
H
exchange and Z
H
exchange can generate significantly corrections to the forward-backward asymmetry
only in a small part of the parameter space.Received: 29 October 2004, Revised: 29 November 2004, Published online: 15 February 2005 相似文献
5.
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
6.
The three-photon ionization in Ca from
S0 ground state is studied. The two-photon process is a near -- resonance process with one of the following bound states: 4s4d
1D2, 4p
P2, 4s6s
1S0, 4
D2 and 4
S0 while the third photon reach either directly the continuum or one of the autoionizing states. The succession of bound states as well as the transitions above the ionization limit are discussed. The dynamics of the multiphoton excitation processes is also discussed and radiative decay of 4
S0 Ca state with two-photon excitation as well as (the measured) decay times of the Ca autoionizing states using the proper line profiles for different quantum numbers has been determined.Received: 29 September 2003, Published online: 18 May 2004PACS:
32.70.-n Intensities and shapes of atomic spectral lines - 32.70.Cs Oscillator strengths, lifetimes, transition moments - 32.80.Fb Photoionization of atoms and ions - 32.80.Rm Multiphoton ionization and excitation to highly excited states (e.g., Rydberg states) 相似文献
7.
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
8.
Noiret I. Schamps J. Danede F. Odou G. Lamiot J. 《The European Physical Journal B - Condensed Matter and Complex Systems》2004,41(1):23-30
Structural properties of two RbCdCl3 samples grown either from the melt or from aqueous solution are studied via X-ray diffraction over a closed temperature cycle between 20
C and 300
C. During cooling step (300
C), the crystal grown from the melt undergoes a phase transition at 110
C that drives it from the cubic structure into a tetragonal structure that still persists at 20
C. It undergoes exactly the reverse phase transition at the same temperature during the heating (
C) step that immediately follows. The other crystal grows from aqueous solution at 20
C in an orthorhombic structure (i.e. not tetragonal as that of the crystal grown from the melt and cooled down to this temperature). During the heating (
C) step, it undergoes a direct orthorhombic-cubic phase transition at 240
C (without passing through the tetragonal phase) whereas, during subsequent cooling (300
C), it does not exhibit the corresponding reverse phase transition but rather exhibits exactly the same cubic-tetragonal phase transition at 110
C as the crystal grown from the melt. However, for both crystals, this tetragonal phase observed at room temperature is unstable and slowly converts into an orthorhombic phase over the course of time. Complementary Differential Scanning Calorimetry (D.S.C.) and Thermo Gravimetric Analysis (T.G.A.) measurements have been carried out over the range (
)
C in order to interpret diffraction experiments.Received: 19 May 2004, Published online: 30 September 2004PACS:
61.10.Nz X-ray diffraction - 64.70.Kb Solid-solid transitions - 65.40.Ba Heat capacity 相似文献
9.
We investigate the influence of a laser field, which is near-resonant to the atomic sodium 32P1/2
32D3/2 transition, on the last bound levels of the A
state in Na2. In a molecular beam experiment level shifts up to
100 MHz and light induced line broadenings were observed using an optical double resonance excitation scheme. Moreover, the coupling laser can reduce the number of bound levels of the A state by one or more units, which effectively means that in the picture of a collision of a 32S1/2 and a 32P1/2-atom the scattering phase is altered by more than
. The observed effects are interpreted as light induced couplings of the A
state, which correlates to the 3s
1/2 + 3p
1/2 asymptote, to the
and
states at the 3s
1/2 + 3d
3/2 asymptote. We performed multi-channel calculations, applying the mapped Fourier grid method, which reproduce our experimentally observed level shifts well.Received: 7 October 2003, Published online: 21 November 2003PACS:
34.50.Rk Laser-modified scattering and reactions - 33.80.-b Photon interactions with molecules - 42.62.Fi Laser spectroscopy 相似文献
10.
Measurements of multiphoton ionization and dissociation of acetone are reported in the wavelength range 582.60-585.80 nm at photon energy resolution of 0.3 cm-1. To our knowledge there are not available results of (3 + 2) REMPI on acetone at 0.01 nm in this region. The experiments were performed using an Nd: YAG-OPO (optical parametric oscillator) laser system coupled to time-of-flight mass spectrometer. The ion yield and the single ion channel are presented. The high-resolution three-photon resonance multiphoton spectrum of the acetone
Rydberg transition is also reported. The experimental results show three dissociation channels of the acetone ion, leading to the products: (CH3CO + ), (CH3
+ ) and (COH + ); the channel CH3COCH
3CO + + CH3 being the most favored. The acetone and acetyl ions are observed in all wavelength range investigated. In addition, we have measured the origin of the
and
transitions, and vibrational bands of the 3s state.Received: 21 March 2004, Published online: 11 May 2004PACS:
33.80.Rv Multiphoton ionization and excitation to highly excited states (e.g., Rydberg states) - 33.15.Ta Mass spectra - 33.80.Gj Diffuse spectra; predissociation, photodissociation 相似文献
11.
Gyürky Gy. Fülöp Zs. Somorjai E. Kiss G. Rolfs C. 《The European Physical Journal A - Hadrons and Nuclei》2004,20(2):355-358
The absolute strengths of the
keV resonance in the
reaction and of the
keV resonance in the
reaction have been measured to
meV and
meV, respectively, in good agreement with previous values. These resonances can be used to measure the absolute acceptance of the recoil separator ERNA to a precision of about 10%.Received: 12 December 2003, Revised: 10 February 2004, Published online: 3 August 2004PACS:
24.30.-v Resonance reactions - 25.40.Lw Radiative capture - 26.20. + f Hydrostatic stellar nucleosynthesis 相似文献
12.
A resonance search has been made in the
invariant-mass spectrum with the ZEUS detector at HERA using an integrated luminosity of
. The decay channels
and
(and the corresponding antiparticle decays) were used to identify
mesons. No resonance structure was observed in the
mass spectrum from more than 60 000 reconstructed
mesons. The results are not compatible with a report of the H1 Collaboration of a charmed pentaquark,
.Received: 14 September 2004, Revised: 29 September 2004, Published online: 9 November 2004 相似文献
13.
We present new experimental data on the highly excited levels in mercury using the two-step laser excitation and optogalvanic detection technique in conjunction with a RF discharge cell. The 6s7s 3S1 intermediate level has been accessed from the 6s6p 3P2 metastable level that is collisionally populated in the mercury discharge in the presence of a buffer gas at a pressure of about 1 Torr. Two beams fromtwo different dye lasers pumped with a common excimer laser were passed through the discharge cell containing mercury vapors. The first laser was tuned to 6s7s 3S1 level whereas the second laser was scanned covering the wavelength region between 544-458 nm. We have observed the 6snp 3P0 (
), 6snp
(
), 6snp
(
) and 6snp
) Rydberg series. The 6snp
Rydberg series to such high n-value has been reported for the first time. The first ionization potential of mercury is determined from the 6snp
Rydberg series as 84184.15
0.05 cm-1. Some collisionally induced parity forbidden transitions have also been located that are identified as 6sns
(
) series.Received: 5 November 2003, Published online: 20 January 2004PACS:
31.50.-x Potential energy surfaces - 32.30.Jc Visible and ultraviolet spectra - 32.80.Rm Multiphoton ionization and excitation to highly excited states (e.g., Rydberg states) 相似文献
14.
A study of Z-boson pair production in e + e- annihilation at center-of-mass energies between 190 GeV and 209 GeV is reported. Final states containing only leptons, (
and
), quark and lepton pairs, (
,
) and only hadrons (
) are considered. In all states with at least one Z boson decaying hadronically, lifetime, lepton and event-shape tags are used to separate
pairs from
final states. Limits on anomalous ZZ
and ZZZ couplings are derived from the measured cross sections and from event kinematics using an optimal observable method. Limits on low scale gravity with large extra dimensions are derived from the cross sections and their dependence on polar angle.Received: 14 July 2003, Published online: 18 December 2003 相似文献
15.
Over 100 high lying level energies of the lowest electronic states
and
in Cs2 are determined in a
-like scheme two-colour photoassociation spectroscopy. The results are analyzed with a coupled channel model using an asymptotic approach, based on nodal lines. From this analysis we determine the long range dispersion coefficient C6 to 6846.2
15.6 a.u. We also obtain the first experimental determination of the amplitude of the asymptotic exchange term.Received: 4 November 2003, Published online: 20 January 2004PACS:
34.20.-b Interatomic and intermolecular potentials and forces, potential energy surfaces for collisions - 32.80.Pj Optical cooling of atoms; trapping - 03.65.Ge Solutions of wave equations: bound states 相似文献
16.
We discuss the time-dependent CP asymmetry of the decay
in an extension of the standard model with both a two Higgs doublet and additional fourth-generation quarks. We show that, although the standard model with a two Higgs doublet and the standard model with fourth-generation quarks alone are not likely to largely change the effective
from the decay
, the model with both an additional Higgs doublet and fourth-generation quarks can easily account for the possible large negative value of
without conflicting with other experimental constraints. In this model, additional large CP violating effects may arise from the flavor-changing Yukawa interactions between neutral Higgs bosons and the heavy fourth-generation down type quark, which can modify the QCD penguin contributions. With the constraints obtained from
processes such as
and
, this model can lead to an effective
as large as - 0.4 in the CP asymmetry of
.Received: 25 March 2004, Revised: 20 April 2004, Published online: 18 June 2004 相似文献
17.
We investigate the physics potential of the annihilation decays
in the standard model and beyond. In a naive factorization approach, the branching ratios are estimated to be
and
. In the framework of QCD factorization, we compute the non-factorizable corrections and get
,
. Future measurements of these decays would be useful for testing the factorization frameworks. The smallness of these decays in the SM makes them sensitive probes of new physics. As an example, we will consider the possible admixture of the (V + A) charge current to the standard (V-A) current. This admixture will give a significant contribution to the decays.Received: 29 August 2003, Revised: 17 January 2004, Published online: 19 March 2004Corresponding author: Y.D. Yang 相似文献
18.
19.
G.?J.?Naga Raju G.?A.?V.?Ramana Murty B.?Seetharami Reddy T.?Seshi Reddy S.?Lakshminarayana S.?Bhuloka Reddy
The L X-ray intensity ratios in the elements Hf, Ta, Re, Ir, Pt, Au and Pb due to proton bombardment at energies from 1 to 5 MeV are measured and compared with the ECPSSR theoretical intensity ratios. The L
/L
l
intensity ratios obtained in the present work are in good agreement with theoretical values while the L
/L
and L
/L
intensity ratios are consistently lower than the theoretical values. This deviation may be explained in terms of multiple ionization effects in M, N and O shells.Received: 27 March 2004, Published online: 6 July 2004PACS:
32.80.Hd Auger effect and inner-shell excitation or ionization - 32.30.Rj X-ray spectra - 41.75.-i Charged-particle beams - 41.75.Ak Positive-ion beams 相似文献
20.
Approximately 438 pb-1 of e + e- data from the OPAL detector, taken with the LEP collider running at centre-of-mass energies of 192-209 GeV, are analyzed to search for evidence of chargino pair production,
, or neutralino associated production,
. Limits are set at the 95% confidence level on the product of the cross-section for the process
and its branching ratios to topologies containing jets and missing energy, or jets with a lepton and missing energy, and on the product of the cross-section for
and its branching ratio to jets. R-parity conservation is assumed throughout this paper. When these results are interpreted in the context of the Constrained Minimal Supersymmetric Standard Model, limits are also set on the masses of the
and
, and regions of the parameter space of the model are ruled out. Nearly model-independent limits are also set at the 95% confidence level on
with the assumption that each chargino decays via a W boson, and on
with the
assumed to decay via a Z0.Received: 15 December 2003, Revised: 16 February 2004, Published online: 23 April 2004 相似文献