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1.
I. D. Petrov T. Peters T. Halfmann S. Aloïse P. O'Keeffe M. Meyer V. L. Sukhorukov H. Hotop 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,40(2):181-193
The even parity mp1/2
5np′ and mp1/2
5nf′ autoionizing resonances of Ar, Kr, and Xe (m=3,4,5) were investigated experimentally and theoretically by one-photon
excitation from lower-lying intermediate levels. In particular, high
resolution measurements for the Ar(nf′), Kr(12p′,8f′), and Xe(8p′)
resonances are reported; lineshape parameters for these resonances have been
derived by a Fano-type analysis, thus yielding reduced resonance widths. The
experimental spectra and the resonance parameters are compared with
theoretical calculations which are based on the configuration interaction
Pauli–Fock approach including core polarization. The measured and
calculated lineshapes are in good agreement. In addition, theoretical predictions are presented
for other resonances, which have not yet been observed experimentally, and some
systematic trends are elucidated. 相似文献
2.
Summary The structure of water in water/AOT/n-heptane reverse micelles has been studied as a function of the [H2O]/[AOT] ratio (W) by using the absorption IR due to O−H stretching modes in the 3800–3000 cm−1 range. The results show that the IR spectra can be expressed as a sum of contributions from bound- and bulk-like water. The
fraction of water in the two ?regions? within the water pool was evaluated as a function ofW. The ?bound? water region seems to hold 3.5 water molecules (corresponding to 7 O−H oscillators) per AOT molecule and its
formation is nearly complete atW>6.
Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Copanello, Italy, July 4–8, 1994. 相似文献
3.
M. Biaye A. Konté N.A.B. Faye A. Wagué 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,13(1):21-25
Energies of singlet doubly excited states 2p2
1D, 3d2
1G, 4f2
1I of He isoelectronic series are calculated in the framework of the variational method by using Hylleraas-type wave functions
and a real Hamiltonian. The results obtained show quantitatively the importance of electron correlation effects in the doubly
excited states and they are in good agreement with some experimental data and other theoretical results.
Received 30 March 2000 and Received in final form 4 July 2000 相似文献
4.
S.I. Themelis Y. Komninos C.A. Nicolaides 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(3):277-293
This paper discusses theory and results on 1P0 doubly excited states (DES) in He and in H- of very high excitation, up to the N
= 25 manifold. Our calculations employed full configuration interaction (CI) with large hydrogenic basis sets and produced correlated
wavefunctions for the four lowest roots at each hydrogenic manifold by excluding open channels and the small contribution
of series belonging to lower thresholds. The suitability of the hydrogenic basis sets for such calculations is justified,
apart from their practicality, by the fact that, by computing from them natural orbitals, the results were shown to be the
same with those of earlier multiconfigurational Hartree-Fock (MCHF) calculations on low-lying DES. In total, 160 states were
computed, most of them for the first time. Their energy spectrum should be of use to possible future photoabsorption experiments.
For certain low-lying DES up to N
= 13, for which previous reliable results are available, comparison of the calculated energies shows good agreement. The correlated
wavefunctions contain systematically chosen single and double excitations from each hydrogenic manifold of interest. From
their analysis, we determined the “goodness" of different quantum numbers and the geometry (average angles and radii) as a
function of excitation. For the Sinano lu-Herrick (
K
,
T
) classification scheme, whose basis is a restricted CI with hydrogenic functions and which has thus far been tested only on
low-lying DES, we established that, whereas T remains a good index as energy increases, K does not. Consequently, a more flexible than K quantum number is needed in order to account for most of the additional correlation. This number, represented by F
=
N
-
K
- 1, where N and K are not good numbers anymore, produces consistently a much higher degree of purity than the (
K
,
T
) scheme does, especially as N increases and as the relative significance of various virtual excitations due to electron correlation increases. Among the
four states of each manifold, in all cases in H- and in most cases in He, the three are of the intrashell type and one is of the intershell type with (
F
,
T
) = (0, 0). The lowest intrashell states and the lowest intershell states exhibit a wide angle geometry tending to 180
°
as N
↦∞.
Received 10 September 2001 and Received in final form 12 November 2001 相似文献
5.
M. C. Martins J. P. Santos A. M. Costa F. Parente 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,39(2):167-172
Wavelengths and oscillator strengths for all
4d4f↦4d2 dipole-allowed fine-structure transitions
in Zr III have been calculated within the Multi-Configuration
Dirac-Fock method with QED corrections. These transitions are
included in the spectrum of some chemically peculiar stars, like the
B-type star χ Lupi observed by the Hubble space telescope. The
results are compared to existing experimental and semi-empirical
data. 相似文献
6.
É. Biémont H.-P. Garnir P.-H. Lefèbvre P. Palmeri L. Philippart P. Quinet D. Rostohar C. J. Zeippen 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,40(1):91-99
Oscillator strengths have been calculated for the transitions depopulating levels of the 3s23p3, 3s3p4 configurations of K V, of the 3s23p2, 3s3p3 configurations of K VI and of the 3s23p, 3s3p2, 3p3 and 3s3p3d configurations of K VII. A multiconfiguration Dirac-Fock method, incorporating the relativistic two-body Breit
interaction and quantum electrodynamics corrections due to self-energy and vacuum polarization, has been used for the calculations.
The reliability of this approach has been tested by comparison with relativistic Hartree-Fock calculations and also with some
experimental measurements performed by beam-foil spectroscopy at a beam energy of 1.7 MeV. 相似文献
7.
J.P. Santos J.P. Marques F. Parente E. Lindroth S. Boucard P. Indelicato 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,1(2):149-163
Structure and QED effects for and levels are calculated for lithiumlike U89+ trough neonlike U82+, lithiumlike Th87+ trough neonlike Th80+ and lithiumlike Bi80+ trough neonlike Bi73+. The results of the first two sets are compared with recent measurements of the transition energy in 3 to 10-electron ions. Good agreement with experiment is found for most of the observed lines. Forty-one
possible transitions are calculated for each ion in the eight ionization states, in the experimental energy range. Twenty-eight
of these transitions have not been observed, nor calculated previously. We also calculate transition rates, branching ratios,
excitation and ionization cross sections and confirm that the thirteen experimental o
bserved transitions correspond to the ones with highest relative intensities. However, we find nineteen more transitions that
could be measured in a more sensitive experiment.
Received: 5 November 1997 / Accepted: 8 December 1997 相似文献
8.
Summary Complete Active-Space Self-Consistent-Field (CAS-SCF) calculations for cubic N8 are presented. We studied the N8↔4N2 reaction inD
4h
symmetry and found its energy release and activation barrier with three different atomic basis sets. The energy release for
this reaction is predicted to be around 526 kcal/mol, while the energy barrier to dissociation is estimated about 159 kcal/mol.
These results are in substantial agreement with previousab initio estimates.
The authors of this paper have agreed to not receive the proofs for correction. 相似文献
9.
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
10.
P. Indelicato J. P. Santos S. Boucard J.-P. Desclaux 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,45(1):155-170
In this paper we review the different relativistic and QED contributions to energies, ionic radii, transition probabilities
and Landé g-factors in super-heavy elements, with the help of the MultiConfiguration Dirac-Fock method (MCDF). The effects
of taking into account the Breit interaction to all orders by including it
in the self-consistent field process are demonstrated. State of the art radiative corrections are included in the calculation
and discussed. We also study the non-relativistic limit of MCDF calculation and
find that the non-relativistic offset can be unexpectedly large. 相似文献
11.
S. Kar Y. K. Ho 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(1):1-8
We have investigated the ground state and the doubly excited 1,3P○ resonance states of plasma-embedded Li+ ion. The plasma effect is taken care of by using a screened Coulomb potential obtained from the Debye model. A correlated
wave function has been used to represent the correlation effect between the charged particles. The ground state of Li+ in plasmas for different screening parameters has been estimated in the framework of Rayleigh-Ritz variational principle.
In addition, a total of 18 resonances (9 each for 1P○ and 3P○ states) below the n=2 Li+ thresholds has been estimated by calculating the density of states using the stabilization method. For each spin state, this
includes four members in the 2snp+ (2≤n ≤5) series, three members in the 2snp- (3≤n ≤5) series, and two members in the 2pnd (n=3, 4) series. The resonance energies and widths for various Debye parameters
ranging from infinity to a small value for these 1,3P○ resonance states along with the ground state energies of Li+ and the Li2+ (1S), Li2+ (2S) threshold energies are reported. Furthermore, the wavelengths for the photo-absorption of lithium ion from its ground
state to such 1P○ resonance states for different Debye lengths are also reported. 相似文献
12.
H. Nieber K. Doll G. Zwicknagl 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,51(2):215-221
We present an ab initio study
of electronic correlation effects
in a molecular cluster derived from
the hexanuclear ferric
wheel [ LiFe6(OCH3)12-(dbm)6] PF6.
The electronic and magnetic properties of this cluster
have been studied with all-electron Hartree-Fock,
full-potential density functional calculations
and multi-reference second-order perturbation theory.
For different levels of correlation,
a detailed study of the impact of the electronic correlation on the exchange parameter
was feasible.
As the main result, we found that
the influence of the bridge oxygen atoms
on the exchange parameter is less intense
than the influence of the apical ligand groups,
which is due to the geometry of the cluster.
With respect to the cluster model approach,
the experimental value of the exchange parameter
was affirmed. 相似文献
13.
M. Mirea 《The European Physical Journal A - Hadrons and Nuclei》1999,4(4):335-341
A fine structure in the 14C decay of 225Ac is predicted quantitatively by accounting dynamical aspects during the disintegration process. Transitions to the excited
states of the daughter nucleus are considered to be mainly directed by the Landau–Zener promotion mechanism in the region
of avoided crossing levels. The level scheme is evaluated with the superasymmetric two–center shell model. The half–lives
are computed considering the cluster decay as a superasymmetric fission process.
Received: 31 July 1998 / Revised version: 27 November 1998 相似文献
14.
Rajendra R. Zope Manoj K. Harbola Rajeev K. Pathak 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,7(2):151-155
The impulse Compton Profiles (CPs) J(q) and the expectation values for some inert gas atoms (He-Kr) are computed and compared within the Harbola-Sahni (HS), Hartree-Fock
(HF) theories and a Self-Interaction-Corrected (SIC) density functional model. The Compton profiles for excited states of
helium atom are also calculated. While the calculated CPs are found to generally agree, they differ slightly from one another
for small values of the Compton parameter q and are in good agreement for large q values. The expectation values within the three theories are also found to be comparable. The HS formalism is seen to mimic HF reasonably
well in the momentum space, establishing the logical consistency of the former.
Received: 11 December 1998 / Received in final form: 20 April 1999 相似文献
15.
N. Simonović P. Grujić 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(1):1-10
The semiclassical spectrum of quadruply highly excited
four-electron atomic systems has been calculated for the plane
model of equivalent electrons. The energy of the system consists
of rotational and vibrational modes within the circular skeleton
orbit approximation, as used in a previous calculation for the
triply excited three-electron systems. The full dynamical analysis
is carried out within the Hamiltonian theory, accounting for the
inertial effects and the complete coupling between different
degrees of freedom. Here we present numerical results for energy
spectrum of the beryllium atom. The lifetimes of the semiclassical
states are estimated via the corresponding Lyapunov exponents. The
vibrational modes relative contribution to the energy levels rises
with the degree of the Coulombic excitation. 相似文献
16.
M. Sabidó J. de Andrés J. Sogas J. M. Lucas M. Albertí J. M. Bofill I. Rabadán A. Aguilar 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,47(1):63-70
The dynamics of collisional processes between Mg atoms and caesium ions is studied using the hemiquantal (HQ) approach with
special attention to the collisional channels leading to Mg(3 1P) and Cs(6 2P) states, for which the corresponding emission excitation functions have been previously measured in our laboratory. The
radial and angular non-adiabatic couplings between the manifold of quasimolecular states have been determined using an ab
initio configuration interaction calculation. The cross-sections for the different channels, as a function of the laboratory
collisional energy, are compared with experimental values. The dynamical calculations indicate that, for the inelastic processes
considered, the range of relevant impact parameters is small, active collisions being of the head-on type.
. 相似文献
17.
I. Sakho A. S. Ndao M. Biaye A. Wague 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,47(1):37-44
Screening Constant by Unit Nuclear Charge (SCUNC) is a new analytical method
suitable for the treatment of the properties of He-like systems. In this
paper, the possibilities of the method are demonstrated for calculating in
the framework of semi-empirical procedure, total energies, total
electron-electron interaction energies and excitation energies for
(ns2)1Se, (np2)1De and (Nsnp)1P° doubly
excited states of He-like ions. The proposed semi-empirical scheme,
leads to accurate results in good agreement as well as with available other
theoretical results than experimental data. 相似文献
18.
A simple formula for correlation energy Ec of the π electron
systems is obtained under an approximation for the electron-electron
interactions. This formula is related directly to square of the bond
order matrix and the nearest-neighbor Coulomb electron-electron
interaction. The influence of the correlation energy on the band
energy gap is discussed. The values of the correlation energy for
polyacetylene (PA) are calculated and can be compared with those for
PA obtained by other methods, including ab initio method. 相似文献
19.
F. Arias de Saavedra E. Buendıa F.J. Gálvez A. Sarsa 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,13(2):201-206
A generalized Hylleraas-type basis set with three nonlinear parameters is proposed to study three-body systems interacting
via coulomb forces within the framework of non-relativistic quantum mechanics. This basis set improves the rate of convergence
with respect to previous ones, specially for non-symmetric systems and excited states of two electron atoms. Accurate binding
energies and other properties for S-states of helium-like ions, muonic molecules and the positronium negative ion are reported.
Received 21 July 2000 and Received in final form 4 October 2000 相似文献
20.
A.V. Shtoff M. Rérat S.I. Gusarov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,15(2):199-208
Floquet theory is used to describe the response of a molecule to applied radiation electric field. The method of ab initio calculation of frequency dependent (hyper)polarizabilities based on combination of perturbation theory with the finite field
method has been developed. Electron correlation is taken into account by means of the CIPSI algorithm. The total wave function
expansion involves spectral, pseudo-spectral states and polynomial terms. The developed approach is applied to the calculation
of the second hyperpolarizability of the lithium hydride molecule subjected to the superposition of harmonic and static electric
fields. The method can be used to calculate the higher order nonlinear properties of molecules.
Received 23 November 2000 and Received in final form 25 March 2001 相似文献