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1.
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
2.
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
3.
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
4.
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
5.
G. Spavieri 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,39(2):157-166
The wave equation for light propagation in slowly moving media, which is
analogous to that of quantum effects of the Aharonov-Bohm type, is
characterized by the interaction momentum
, related to the flow
. In effects of the Aharonov-Bohm type the interaction momentum
is related to the momentum of the electromagnetic (em) fields, that
characterizes an em flow
. It is shown that in both cases
has the same physical origin. Calculation of the interaction em momentum
for the light wave dragged by the flow yields exactly the
Fresnel-Fizeau momentum. These results corroborate the validity of the
magnetic model for light and highlight the role and relevance of the em
momentum in new effects of classical and quantum physics. A tentative test
of an astrophysical Fizeau-Aharonov-Bohm effect is discussed. 相似文献
6.
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
7.
J. P. Marques F. Parente P. Indelicato 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(3):457-465
In this paper, we used the multiconfiguration Dirac-Fock method to compute with high precision the influence of the hyperfine
interaction on the [Ar]
P0 level lifetime in Zn-like ions for stable and some quasi-stable isotopes of nonzero nuclear spin between Z=30 and Z=92. The
influence of this interaction on the
[Ar]
P
P0 separation energy is also calculated for the same ions. 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.
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
10.
I. Vilfan 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,51(2):277-284
The properties of
nanowires were investigated with
ab initio calculations based on the density-functional theory.
The molecules build weakly coupled one-dimensional chains, like
and Mo6S9-xIx, and the crystals are
strongly uniaxial in their mechanical and electronic properties.
The calculated moduli of elasticity and resilience along the chain axis are
c11 = 320 GPa and ER = 0.53 GPa, respectively.
The electronic band structure and optical conductivity indicate
that the
crystals are good quasi-one-dimensional conductors.
The frequency-dependent complex dielectric tensor ε, calculated
in the random-phase approximation, shows a strong Drude peak in
ε∥, i.e., for the electric field polarised parallel to
the chain axis, and several peaks related to interband transitions.
The electron energy loss spectrum is weakly anisotropic and has a strong peak
at the plasma frequency ħωp ≈20 eV.
The stability analysis shows that
is metastable against the
formation of the layered
. 相似文献
11.
With the aim to provide a reliable scheme for efficient laser excitation of the potassium D2 line over long periods of time, we have developed a robust stabilization of a single mode laser of frequency f
0 = (f
12 + f
23)/2 onto a crossover peak in the saturation spectrum of the 39K(D2) line (4s
2S
P
. The two hyperfine transitions
(frequency f
12) and
(frequency f
23) are simultaneously excited by the first order sidebands
of the laser beam (f
0), generated by its electro-optical modulation at the frequency f
EOM
= (f
12-f
23)/2. In this way stable excitation of the two transitions on their proper frequencies is achieved and hyperfine pumping compensated.Received: 10 March 2004, Published online: 29 June 2004PACS:
39.30. + w Spectroscopic techniques - 32.80.Bx Level crossing and optical pumping - 42.60.Fc Modulation, tuning, and mode locking 相似文献
12.
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
13.
Previously unaccessible plasma states of matter can be produced by irradiation with powerful lasers. The interactions within the plasma shift and distort the spectral lines corresponding to radiative transitions. The shape of the spectra is determined by two frequencies characterizing the fluctuations of the electric microfield in the plasma and the Stark splitting of the lines. Traditionally the fluctuations due to the motion of the ions are considered as sufficiently slow and weak to be treated in a linear quasi-static approximation, while the electrons are accounted for in an instantaneous impact approximation. Here also the intermediate regimes and strongly correlated ions are investigated. For that purpose the microfield fluctuations are calculated by molecular dynamics computer simulations. They are then used as input in a numerical solution of the time-dependent Schrödinger equation for the radiating electron. The shape of the Ly
-line in H and in Al is investigated in the intermediate regime. The calculations are in agreement with recent experiments on the Ly
and Ly
lines in Al.Received: 7 January 2004, Published online: 15 April 2004PACS:
32.30.Rj X-ray spectra - 32.70.Jz Line shapes, widths, and shifts - 52.25.Os Emission, absorption, and scattering of electromagnetic radiation - 52.65.Yy Molecular dynamics methods 相似文献
14.
É. Biémont A. Ellmann P. Lundin S. Mannervik L.-O. Norlin P. Palmeri P. Quinet D. Rostohar P. Royen P. Schef 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(2):211-219
The difficulty associated with an accurate determination of transition rates for forbidden lines in lowly ionized heavy elements
is illustrated in the case of Nd II. We have investigated the radiative decay of the low-lying metastable levels in Nd+ including the two levels
K11/2 and
I13/2. In these two particular cases, using different theoretical approaches, we find that the decay is dominated by the M1 channels
but that the E2 contributions are of the same order of magnitude. These levels have also been studied experimentally by lifetime
measurements with the heavy ion storage ring CRYRING of Stockholm University. The difficulties encountered when performing
such experiments are underlined and discussed. 相似文献
15.
Van Hooydonk G. 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2005,32(3):299-317
The historical importance of the original
quantum mechanical bond theory proposed by Heitler and London in 1927 as well
as its pitfalls are reviewed. Modern ab initio treatments of H-
systems are inconsistent with the logic behind algebraic Hamiltonians
H± =H 0 ± H for charge-symmetrical and charge-asymmetrical 4 unit charge systems
like H2 and H
. Their eigenvalues E± =E 0±
are exactly those of 1927 Heitler-London (HL) theory. Since these
2 Hamiltonians are mutually exclusive, only the attractive one can apply for stable natural molecular H2. A wrong choice leads to problems with antiatom
. In line with earlier results on band and line spectra, we now prove
that HL chose the wrong Hamiltonian for H2. Their theory explains the stability
of attractive system H2 with a repulsive Hamiltonian H0 + H instead
of with the attractive one H0-H, representative for
charge-asymmetrical system H
. A new second order symmetry effect is detected in
this attractive Hamiltonian, which leads to a 3-dimensional structure for
the 4-particle system. Repulsive HL Hamiltonian H+ applies at long
range but at the critical distance, attractive charge-inverted Hamiltonian
H- takes over and leads to bond H2 but in reality, H
, for which we give an analytical proof. This analysis confirms and
generalizes an earlier critique of the wrong long range behavior of
HL-theory by Bingel, Preuss and Schmidtke and by Herring. Another wrong
asymptote choice in the past also applies for atomic antihydrogen
, which has hidden the Mexican hat potential for natural hydrogen. This
generic solution removes most problems, physicists and chemists experience
with atomic
and molecular H
, including the
problem with antimatter in the Universe. 相似文献
16.
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
17.
A semi-phenomenological theory of variable-range hopping (VRH) is developed for two-dimensional (2D) quasi-one-dimensional
(quasi-1D) systems such as arrays of quantum wires in the Wigner crystal regime. The theory follows the phenomenology of Efros,
Mott and Shklovskii allied with microscopic arguments. We first derive the Coulomb gap in the single-particle density of states,
g(ε), where ε is the energy of the charge excitation. We then derive the main exponential dependence of the electron conductivity
in the linear (L), i.e. σ(T) ∼exp [-(TL/T)γL], and current in the non-linear (NL), i.e.
, response regimes (
is the applied electric field). Due to the strong anisotropy of the system and its peculiar dielectric properties we show
that unusual, with respect to known results, Coulomb gaps open followed by unusual VRH laws, i.e. with respect to the disorder-dependence
of TL and
and the values of γL and γNL. 相似文献
18.
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
19.
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
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