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1.
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
2.
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
3.
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
4.
A pair
of interacting Kerr oscillators treated as a master coupler sending chaotic or hyperchaotic signals to its slave copy
is considered. We synchronize a with A and b with B through two communication channels
and
. The effect of synchronization is non-simultaneous, the pairs
and
have different times of synchronization. It is possible to synchronize an individual pair, for example,
when its communication channel
is turned off, provided that the second channel for the pair
is turned on. The resulted synchronization is termed induced. The efficiencies of the presented synchronization precesses are studied.Received: 20 February 2003, Published online: 29 April 2003PACS:
05.45.Xt Synchronizations; coupled oscillators - 05.45.Pq Numerical simulations of chaotic systems - 42.65.Sf Dynamics of nonlinear optical systems; optical instabilities, optical chaos and complexity, and optical spatio-temporal dynamics 相似文献
5.
The distorted wave Born approximation (DWBA) with the spin averaged static exchange potential has been used to calculate the triple differential cross-sections (TDCSs) for Ne (2s
2) ionization by electron impact in coplanar to perpendicular plane symmetric geometry at 110.5 eV incident electron energy. The present theoretical results at gun angles
(coplanar symmetric geometry) and
(perpendicular plane geometry) are in satisfactory agreement with the available experimental data. A deep interference minimum appears in the TDCS in the coplanar symmetric geometry and a strong peak at scattering angle
caused by the single collision mechanism has been observed in the perpendicular plane geometry. The TDCSs at the gun angles
, and
are predicted.Received: 16 July 2002, Published online: 22 July 2003PACS:
34.80.Gs Molecular excitation and ionization by electron impact - 34.80.Dp Atomic excitation and ionization by electron impact 相似文献
6.
The purpose of this paper is to study the temperature evolution during the interaction of a plasma with an insulating wall in polyethylene ((CH2)
n
) and polyoxymethylene ((CH2O)
n
). The plasma is initiated by means of a capacitor bank discharge in a copper fuse wire. Due to the energy release the ablation of the insulating wall produces some insulating vapours in addition to the copper vapours corresponding to the wire vaporization. Using neutral copper line intensity ratio assuming a Bo ltzmann distribution we obtain a temperature evolution from
11 000 K to
24 000 K in the first few hundreds microseconds of the discharge. For later times the copper lines are strongly self-absorbed and make impossible the diagnostic in a spectroscopic way. Hence the temperature is deduced from the comparison between the experimental and calculated electrical conductivity. So for the decrease of the current the temperature evolves from
21 000 K down to
6 000 K and depends on the p lasma density. The results and the reliability of the two methods are discussed.Received: 25 July 2003, Published online: 14 October 2003PACS:
52.25.Kn Thermodynamics of plasmas - 52.70.Kz Optical (ultraviolet, visible, infrared) measurements - 52.80.Wq Discharge in liquids and solids 相似文献
7.
The interaction of classical and quantized electromagnetic fields with an ensemble of atoms in an optical cavity is considered. Four fields drive a double-
level scheme in the atoms, consisting of a pair of
systems sharing the same set of lower levels. Two of the fields produce maximum coherence,
, between the ground state sublevels 1 and 2. This pumping scheme involves equal intensity fields that are resonant with both the one- and two-photon transitions of the
system. There is no steady-state absorption of these fields, implying that the fields induce a type Electromagnetically-Induced Transparency (EIT) in the medium. An additional pair of fields interacting with the second
system, combined with the EIT fields, leads to squeezing of the atom spin associated with the ground state sublevels. Our method involves a new mechanism for creating steady-state spin squeezing using an optical cavity. As the cooperativity parameter C is increased, the optimal squeezing varies as C
-1/3. For experimentally accessible values of C, squeezing as large as 90% can be achieved.Received: 28 May 2003, Published online: 12 August 2003PACS:
42.50.Lc Quantum fluctuations, quantum noise, and quantum jumps - 42.50.Dv Nonclassical states of the electromagnetic field, including entangled photon states; quantum state engineering and measurements - 42.65.Pc Optical bistability, multistability, and switching, including local field effects 相似文献
8.
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
9.
The H Collaboration 《The European Physical Journal C - Particles and Fields》2003,29(4):497-513
Inclusive jet cross sections are measured in photoproduction at HERA using the H1 detector. The data sample of
events in the kinematic range of photon virtualities
and photon-proton centre-of-mass energies
represents an integrated luminosity of
. Jets are defined using the inclusive
algorithm. Single- and multi-differential cross sections are measured as functions of jet transverse energy ET jet and pseudorapidity
in the domain
and
. The cross sections are found to be in good agreement with next-to-leading order perturbative QCD calculations corrected for fragmentation and underlying event effects. The cross section differential in ET jet, which varies by six orders of magnitude over the measured range, is compared with similar distributions from
colliders at equal and higher energies.Received: 24 February 2003, Revised: 26 May 2003, Published online: 11 July 2003 相似文献
10.
H. Prakash P. Kumar 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(2):359-363
We study amplitude-squared squeezing of the Hermitian operator Zθ=Z1
cosθ+Z2 sin θ, in the most general superposition state
, of two coherent states
and
. Here operators Z1,2 are defined by
, a is annihilation operator, θ is angle, and
complex numbers C1,2 , α, β are arbitrary and only
restriction on these is the normalization condition of the state
. We define the condition for a state
to be amplitude-squared squeezed for the operator Zθ
if squeezing parameter
, where N=a+a and
. We find
maximum amplitude-squared squeezing of Zθ in the superposed
coherent state
with minimum value 0.3268 of the
parameter S for an infinite combinations with α- β= 2.16
exp [±i(π/4) + iθ/2],
and with
arbitrary values of (α+β) and θ. For this minimum
value of squeezing parameter S, the expectation value of photon number can
vary from the minimum value 1.0481 to infinity. Variations of the parameter
S with different variables at maximum amplitude-squared squeezing are also
discussed. 相似文献
11.
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
12.
M. Z.M. Kamali K. Ratnavelu Y. Zhou 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(2):267-279
The recent theoretical work by Bartlett et al. [J. Phys. B 38, L95 (2005)] and the latest measurements on the reduced Stokes parameters
,
and
for 54.4 eV electron impact excitation of the 2p state atomic hydrogen by Williams and Mikosza [J. Phys. B 39, 4113 (2006)] has motivated the present work. A coupled-channel-optical calculation with 9 and 12 atomic states supplemented
with the continuum optical potentials for the stronger coupling channels has been performed. The calculated n = 2 and n =
3 differential cross sections and the reduced Stokes parameters are comparable with the state-of-the art calculations. There is closer agreement between the present calculations and the experimental measurements for the reduced
Stokes parameters
and
in the n = 2p excitation at 54.4 eV. The present CCO calculations also display good accord with the limited experimental
data for the reduced Stokes parameters in the n=3p excitation. 相似文献
13.
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
14.
production in
interactions has been detected via its decays into
,K
+
K
-
K
+
K
- and
in the data taken with the DELPHI detector at LEP1 and LEP2 energies. The two-photon radiative width averaged over all observed decay channels is
= 13.9
2.0 (stat.)
1.4(syst.)
2.7 (BR) keV. No direct decay channel
has been observed. An upper limit
< 5.5 keV at 95% confidence level has been evaluated for this decay mode.Received: 3 July 2003, Published online: 7 November 2003 相似文献
15.
E. Boos H.-U. Martyn G. Moortgat-Pick M. Sachwitz A. Sherstnev P. M. Zerwas 《The European Physical Journal C - Particles and Fields》2003,30(3):395-407
The basic parameters of supersymmetric theories can be determined at future e
+
e
- linear colliders with high precision. We investigate in this report how polarisation measurements in
and
or
decays to
leptons and t quarks plus neutralinos or charginos can be used to measure
(in particular for large values) and to determine the trilinear couplings
, A
t
and A
b
in sfermion pair production.Received: 17 April 2003, Revised: 3 July 2003, Published online: 29 August 2003 相似文献
16.
We have performed a series of experiments to observe 11 Stark-induced E1 transitions from the 15650.55 cm-1 level to higher levels with odd parity in samarium (Sm) with optical double-resonance technique. Five Stark-induced E1 transition to the 28233.08, 28613.22, 28913.97, 29041.31 and 29130.03 cm-1 levels have been observed. In order to investigate the contributors to the Stark-induced E1 transition, we have measured scalar and tensor polarizabilities for the observed Stark-induced E1 transitions. Clear Stark splittings were observed for the levels 28233.08 and 28613.22 cm-1, and their tensor polarizabilities were determined for each isotope. Scalar polarizabilities were determined for the 28233.08, 28613.22, 28913.97 and 29130.03 cm-1 levels for the first time. Among them, scalar polarizability for the 28233.08 cm-1 level was the largest in magnitude and was 3.60(10) x 103 kHz/(kV/cm)2 for
Sm. We noticed that both scalar and tensor polarizabilities of the 28233.08 cm-1 level depend on the isotope; the difference of magnitude of the scalar and tensor polarizabilities between
Sm and
Sm were remarkably large and were about 10 and 6 percent, respectively.Received: 10 February 2003, Published online: 30 July 2003PACS:
32.60.+i Zeeman and Stark effects - 32.10.Dk Electric and magnetic moments, polarizabilityD. Angom: Present address: Physical Research Laboratory, Navarangpura, Ahmedabad 380 009, India. 相似文献
17.
Benhamou M Himmi M Benzouine F Bettachy A Derouiche A 《The European physical journal. E, Soft matter》2004,13(4):353-358
We re-examine here the computation of the effective force between two star-polymers of respective numbers of branches f1 and f2, immersed in a common
-solvent. Such a force originates essentially from the repulsive three-body interactions. To achieve this, we take advantage of some established results using renormalization theory for three-dimensional star-polymers, or conformal invariance for two-dimensional ones. We first show that, in dimension d = 3, the force,
, decreases with the center-to-center distance r as
, with the exact universal amplitude
. Second, in dimension d = 2, we find that the force decays more slowly as
, with the exact universal amplitude
. For high distances compared to the gyration radius,
, of a single polymer chain at the
-point, an exponential decay of the force is expected.Received: 3 February 2004, Published online: 24 May 2004PACS:
61.25.Hq Macromolecular and polymer solutions; polymer melts; swelling - 05.20.-y Classical statistical mechanics 相似文献
18.
M. Boglione M. R. Pennington 《The European Physical Journal C - Particles and Fields》2003,30(4):503-512
A guide to the composition of the enigmatic f
0(980) and a
0(980) states is their formation in
-radiative decays. Precision data are becoming available from the KLOE experiment at the DA
NE machine at Frascati, as well as results from SND and CMD-2 at VEPP-2M at Novosibirsk. We show how the coupling of the f
0(980) to this channel can be extracted from these, independently of the background provided by
production. To do this we use the fact that the behaviour of both the f
0(980) and
cannot be determined by these data alone, but is strongly constrained by experimental results from other hadronic processes as required by unitarity. We find that the resulting coupling for the
is
GeV with a background that is quite unlike that assumed if unitarity is neglected. This provides an object lesson in how unitarity teaches us to add resonances. Not surprisingly the result is crucially dependent on the pole position of the f
0(980), for which there are still sizeable uncertainties. At present this leads to an uncertainty in the
branching ratio which can only be fixed by further precision data on the f
0(980). Nevertheless, the
is now the same order of magnitude as the experimental
.Received: 25 March 2003, Published online: 5 September 2003 相似文献
19.
Exotic, neutron-rich proton-induced spallation products of 232Th and 238U obtained from the PS Booster ISOLDE facility have been investigated by
-
,
-
coincidence and spectrum-multiscaling measurements. A new method for the reduction of isobaric contamination enabled to study the unknown region beyond 208Pb for the decay chain A = 217. A new isotope 217Bi with a half-life of
s was discovered and its
-decay studied. For the first time, a half-life value of
s for the
-decay of 217Po was measured.Received: 3 March 2003, Revised: 13 May 2003, Published online: 30 September 2003PACS:
23.20.Lv
transitions and level energies - 23.60.+e
decay - 27.80.+w 190
A
219 - 29.30.Kv X- and
-ray spectroscopyV. Fedoseyev: Present address: ISOLDE, CERN-PPE, CH-1211, Geneva 23, Switzerland.M. Górska: Present address: GSI, Darmstadt, D-64220, Germany.M. Huhta: Present address: Nokia, Tampere, Finland. 相似文献
20.
C. Y. Xie X. H. Zhou Y. Zheng Y. H. Zhang Z. Liu Z. G. Gan T. Hayakawa M. Oshima T. Toh T. Shizuma J. Katakura Y. Hatsukawa M. Matsuda H. Kusakari M. Sugawara K. Furuno T. Komatsubara 《The European Physical Journal A - Hadrons and Nuclei》2004,19(1):7-9
The level structure of the doubly odd nucleus 146Tb has been studied via the 118Sn(32S, 1p3n) reaction using techniques of in-beam
-ray spectroscopy. Measurements of
-ray anisotropies, X-
and
-
-t coincidences were performed with 12 BGO(AC)HPGe detectors. Based on the measured results, the level scheme of 146Tb has been revised significantly and extended up to an excitation energy of 8.39 MeV. The level structure has been interpreted qualitatively by coupling an h
11/2 proton-particle and an h
11/2 neutron-hole to the excited states in the 146Gd core.Received: 3 July 2003, Published online: 26 November 2003PACS:
23.20.Lv
transitions and level energies - 27.60. + j
相似文献