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1.
D. Wang J. Qi M. F. Stone O. Nikolayeva B. Hattaway S. D. Gensemer H. Wang W. T. Zemke P. L. Gould E. E. Eyler W. C. Stwalley 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2004,31(2):165-177
We have observed the photoassociative spectra of colliding ultracold 39K and 85Rb atoms to produce KRb* in all eight bound electronic states correlating with the 39K (4s) + 85Rb(5p
1/2 and 5p
3/2) asymptotes. These electronically excited KRb* ultracold molecules are detected after their radiative decay to the metastable triplet (a
state and (in some cases) the singlet (X
ground state. The triplet (a
ultracold molecules are detected by two-photon ionization at 602.5 nm to form KRb + , followed by time-of-flight mass spectroscopy. We are able to assign a majority of the spectrum to three states (2(0 + ), 2(0-), 2(1)) in a lower triad of states with similar C
6 values correlating to the K(4s) + Rb (5p
1/2) asymptote; and to five states in an upper triad of three states (3(0 + ), 3(0-), 3(1)) and a dyad of two states (4(1), 1(2)), with one set of similar C
6 values within the upper triad and a different set of similar C
6 values within the dyad. We are also able to make connection with the short-range spectra of Kasahara et al. [J. Chem. Phys. 111, 8857 (1999)], identifying three of our levels as v = 61, 62 and 63 of the 1
4(1) state they observed. We also argue that ultracold photoassociation to levels between the K(4s) + Rb (5p
3/2) and K(4s) + Rb (5p
1/2) asymptotes may be weakly or strongly predissociated and therefore difficult to observe by ionization of a
(or X
molecules; we do know from Kasahara et al. that levels of the 1
4(1) and 2
5(1) states in the intra-asymptote region are predissociated. A small fraction (
1/3) of the triplet (a
ultracold molecules formed are trapped in the weak magnetic field of our magneto-optical trap (MOT).Received: 22 September 2004, Published online: 23 November 2004PACS:
33.20.Fb Raman and Rayleigh spectra (including optical scattering) - 34.20.Cf Interatomic potentials and forces - 33.80.Ps Optical cooling of molecules; trapping 相似文献
2.
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
3.
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.
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
6.
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
7.
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
8.
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
9.
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
10.
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
11.
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
12.
For a homogeneous quantum network of N subsystems with n levels each we consider separable generalized Werner states. A generalized Werner state is defined as a mixture of the totally mixed state and an arbitrary pure state
:
with a mixture coefficient
. For this density operator
to be separable,
will have an upper bound
. Below this bound one should alternatively be able to reproduce
by a mixture of entirely separable input-states. For this purpose we introduce a set of modules, each contributing elementary coherence properties with respect to a generalized coherence vector. Based on these there exists a general step-by-step mixing process for any
. For
being a cat-state it is possible to define an optimal process, which produces states right up to the separability boundary (
).Received: 3 December 2002, Published online: 29 July 2003PACS:
03.65.Ud Entanglement and quantum nonlocality (e.g. EPR paradox, Bells inequalities, GHZ states, etc.) - 03.67.-a Quantum information - 03.65.-w Quantum mechanics 相似文献
13.
Tau lepton decays with open strangeness in the final state are measured with the OPAL detector at LEP to determine the strange hadronic spectral function of the
lepton. The decays
,
and
with final states consisting of neutral and charged kaons and pions have been studied. The invariant mass distributions of
of these final states have been experimentally determined. Monte Carlo simulations have been used for the remaining
and for the strange final states including
mesons. The reconstructed strange final states, corrected for resolution effects and detection efficiencies, yield the strange spectral function of the
lepton. The moments of the spectral function and the ratio of strange to non-strange moments, which are important input parameters for theoretical analyses, are determined. Furthermore, the branching fractions
and
have been measured.Received: 18 February 2004, Revised: 30 April 2004, Published online: 15 June 2004 相似文献
14.
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
15.
Surface structures in the Te/Ni(111) system are revealed by using reflection high-energy electron diffraction combined with X-ray and ultraviolet photoelectron spectroscopies. At a 0.33 mono-layer (ML)-Te/Ni(111) surface, a reversible structural phase transition is observed with a transition temperature Tc of 380
C. The diffraction pattern from the low temperature phase is accompanied by streaks. The high and low temperature phases are characterized by
and
rectangle, respectively. The mechanism of the phase transition is explained by the order-disorder transition with a rumpled chain model. Both 0.51 ML- and 0.44 ML-Te/Ni(111) surfaces exhibit the complex diffraction patterns accompanied by diffuse streaks. These surface structures are characterized by the
rectangle and
, respectively. All diffuse streaks obtained at the above surfaces are consistently interpreted in the view of the ill-ordered arrangements of the well-ordered
linear chains. It is shown that the
linear structure is the key in the Te/Ni(111) system.Received: 1 December 2003, Published online: 20 April 2004PACS:
61.14.Hg Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED) - 68.65.-k Low-dimensional, mesoscopic, and nanoscale systems: structure and nonelectronic properties - 64.60.Cn Order-disorder transformations; statistical mechanics of model systems 相似文献
16.
G. Poletti F. Orsini D. Batani A. Bernardinello T. Desai J. Ullschmied J. Skala B. Kralikova E. Krousky L. Juha M. Pfeifer Ch. Kadlec T. Mocek A. Präg O. Renner F. Cotelli C. Lora Lamia A. Zullini 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2004,30(2):235-241
Soft X-ray Contact Microscopy (SXCM) of Caenorhabditis elegans nematodes with typical length
m and diameter
m has been performed using the PALS laser source of wavelength
m and pulse duration
ps. Pulsed soft X-rays were generated using molybdenum and gold targets with laser intensities
W/cm2. Images have been recorded on PMMA photo resists and analyzed using an atomic force microscope operating in contact mode. Cuticle features and several internal organs have been identified in the SXCM images including lateral field, cuticle annuli, pharynx, and hypodermal and neuronal cell nuclei.Received: 18 February 2004, Published online: 29 June 2004PACS:
42.62.Be Biological and medical applications - 07.85.Tt X-ray microscopes - 87.59.Bh X-ray radiographyA color version of the figures is available in electronic form at . 相似文献
17.
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
18.
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
19.
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
20.
Based on the corrected sum rules and generalized virial identities, we derive an expression for all modes of excitation spectrum of interacting Bose gases at finite atom numbers in axially anisotropic potentials, in terms of the N-body ground state average. Using the variational Gaussian calculation for the ground-state wave function, its explicit analytic formulas are obtained. These results show clearly the dependence of excitation spectrum on the interaction strength parameter
and trap geometry parameter
for the system with N = 1 through
. For
and 1 the dependences have simple and intuitive physical interpretations. We compare the low-lying excitation spectra with the existing numerical results and make quantitative predications for future experiments and numerical simulation for higher-lying excitation modes.Received: 18 February 2004, Published online: 20 April 2004PACS:
67.40.Db Quantum statistical theory; ground state, elementary excitations - 67.90. + z Other topics in quantum fluids and solids; liquid and solid helium 相似文献