共查询到20条相似文献,搜索用时 31 毫秒
1.
A. A. Preobrazhenskaya S. O. Adamson D. D. Kharlampidi A. I. Dement’ev 《Russian Journal of Physical Chemistry B, Focus on Physics》2014,8(1):22-29
By the example of the lowest resonance state of the H? system, two versions of the stabilization method are considered: with introduction of an external potential into the Hamiltonian and with enlargement of the single-particle function basis. A comparison of the results suggests the possibility of applying these methods to calculating the resonance parameters in many-electron systems. 相似文献
2.
The nonthermal effects on the doubly-excited resonance states of two-electron positive ions are investigated in Lorentzian astrophysical plasma environments using highly correlated Hylleraas-type wave functions in the framework of the stabilization method. Resonance parameters (resonance position and width) for Li+, Be2+ and B3+ are reported for the first time as functions of the spectral index and plasma parameter. 相似文献
3.
We have investigated the doubly excited 1,3
P
e resonance states of positronium negative ion with Coulomb and screened Coulomb potentials using highly accurate correlated
exponential wavefunctions. For Coulomb interaction, the stabilization and the complex-rotation methods are employed to extract
resonance parameters (resonance positions and widths). We have obtained two 1
P
e resonances and three 3
P
e resonances below the n = 3 Ps threshold. In addition to Feshbach resonances lying below n = 3 Ps threshold, we have calculated one 3
P
e shape resonances lying above the Ps (n = 2) threshold. For screened Coulomb (Yukawa) interaction, we employ the stabilization method to extract resonance parameters
as functions screening parameter. The resonance energies and widths for 1,3
P
e resonance states of Ps− below the n = 3 Ps threshold for different screening parameters ranging from infinity (Coulomb case) to small values are reported, along
with the Ps(3S) and Ps(3P) threshold energies. The screened Coulomb results for the 1,3
P
e resonance states are reported for the first time in the literature. 相似文献
4.
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
5.
Semimicroscopic approach based on the continuum version of the random-phase approximation and on a phenomenological method for taking into account the fragmentation effect is used to describe quantitatively basic relaxation parameters of the Gamow-Teller resonance in magic and nearmagic nuclei. For the 208Bi nucleus, the results obtained by calculating the resonance parameters in question are compared with respective experimental data. 相似文献
6.
We have investigated the doubly excited 2s2p
3
P
o
and 2s3p
1
P
o
resonance states of H− embedded in a model plasma environment. Plasma effects are taken care of by using a screened Coulomb (Yukawa-type) potential.
Correlated wave functions are used to represent the correlation effect between the charged particles. The density of resonance
states has been calculated using the stabilization method. The calculated resonance energies and widths for various screening
parameters are reported. 相似文献
7.
S. O. Adamson D. D. Kharlampidi A. A. Preobrazhenskaya A. I. Dement’ev 《Russian Journal of Physical Chemistry B, Focus on Physics》2017,11(6):894-902
The parameters of the lowest 2S resonance state of the He? system were calculated using the Coulomb potential stabilization method. It was found that the errors of the resonance energy and width have the same character as that in the earlier studied two-electron systems H?, He, and Li+. It was shown that the errors can be minimized using a single-electron basis sets, which provides the best reproduction of the low-lying states of the helium atom. 相似文献
8.
M.V. Kossov 《The European Physical Journal A - Hadrons and Nuclei》2002,14(3):377-392
Photonuclear interaction cross-sections from the GEANT4 database are approximated for all nuclei and all energies (from the
hadron production threshold to about 40 TeV). The approximation methods in the giant-dipole resonance region, nucleon resonance
region, and high-energy region are improved with respect to existing approximations. As an application of the approximation
for photonuclear cross-sections, an improved method of calculating electronuclear cross-sections is developed. The interaction
cross-section of virtual photons with nuclei at high Q2 are approximated and a simple algorithm for describing the electronuclear reactions, including high-Q2 scattering, is proposed.
Received: 22 February 2002 / Accepted: 6 May 2002 相似文献
9.
We have investigated the doubly excited 1
D
e
resonance states of Ps− interacting with pure Coulomb and screened Coulomb (Yukawa) potentials employing highly correlated wavefunctions. For pure
Coulomb interaction, in the framework of stabilization method and complex coordinate rotation method we have obtained two
resonances below the n = 2 threshold of the Ps atom. For screened Coulomb interaction, we employ the stabilization method to extract resonance parameters.
Resonance energies and widths for the 1
D
e
resonance states of Ps− for different screening parameter ranging from infinity (pure Coulomb case) to a small value are also reported. 相似文献
10.
S. Kar Y. K. Ho 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,57(1):13-19
The doubly excited 1,3D○ resonance states of Ps- associated
with N=3, N=4 and N=5 Ps thresholds have been investigated using highly
accurate correlated wave functions with exponents generated by a quasirandom
process. Resonance parameters (both resonance positions and widths) are
extracted in the framework of the stabilization method and the complex
coordinate rotation method. In addition to many Feshbach resonances below
the various Ps thresholds, we have identified two 1
D○ shape
resonances with one each lying above the N=3 and N=4 thresholds, respectively,
and two 3
D○ shape resonances with one each lying above the N=3 and
N=5 thresholds, respectively. The 1
D○ shape resonance associated
with N=3 Ps threshold and some other Feshbach resonances are reported for the
first time in the literature. 相似文献
11.
Three different approaches to taking into account exchange effects in heavy-ion collisions are studied. Within the first of
them, the lowest eigenstates of the Hamiltonian are treated as forbidden states. In the second approach, the eigenstates of
the normalization kernel of the resonating-group model that correspond to zero eigenvalues are treated as forbidden states.
The third approach takes additionally into account semiforbidden states. The 16O + 16O system is considered. A hybrid approach that combines the methods of discrete and continuous mathematics is developed for
calculating the widths of narrow resonance states. The resonance width calculated within the approach that takes into account
semiforbidden states proves to be sharply different from the widths obtained within traditional approaches. 相似文献
12.
Sumana Chakraborty Yew Kam Ho 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,49(1):59-65
This work presents an investigation on the doubly excited 1S
e
autoionizing states of screened helium atom lying below the n = 4 threshold of the He+ ion. The potential generated in this system is represented by a Yukawa type potential. We have employed complex-coordinate
rotation method, as it is a powerful scheme to study high lying resonances. Hylleraas type wave function is used to consider
the correlation effect between all the charged particles. Our resonance parameters for the resonances lying below the He+ (n = 2) threshold agree well with those of the existing calculations by using the stabilization method. Resonances associated
with higher thresholds are new calculations. All the present results are well converged with basis length N = 444. 相似文献
13.
M. L. Falin K. I. Gerasimov V. A. Latypov A. M. Leushin A. Hoefstaetter 《Applied magnetic resonance》2011,40(1):65-73
A trigonal Yb3+ paramagnetic center in the CsCaF3 single crystal was studied by magnetic resonance and optical spectroscopy methods. The structural model of the complex and
the empirical energy level scheme were established. The transferred hyperfine interaction parameters and the crystal field
ones were determined. The crystal field parameters were used to analyze the lattice distortions in the vicinity of Yb3+ using the superposition model. 相似文献
14.
Donald D. Cobb 《Journal of Quantitative Spectroscopy & Radiative Transfer》1976,16(11):919-929
A model is derived for the resonance absorption of molecular bands composed of Lorentzian lines that is suitable for calculating fluorescence from irradiated air. The model is based on an explicit functional form derived for the resonance absorption of a single Lorentzian line which properly accounts for the possibility of unequal emission and absorption line widths. A procedure for rapid numerical computation of this function is given. This function yields a model for the resonance absorption of molecular bands composed of either overlapping or separated lines. A significant savings in computation time is obtained by using the model in place of exact expressions for resonance absorption. Examples are given for the resonance absorption of the N2+ First Negative band system. 相似文献
15.
A. Ghoshal Y. K. Ho 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,56(2):151-156
The 2s2 1Se2s^2~^1{\rm S}^e autoionization resonance states of the positronium negative ion (Ps-) in exponential cosine-screened Coulomb potentials (ECSCP) are investigated using stabilization method. Highly correlated
wave functions for Ps- are used to take into account the correlation effect of the charged particles. Results for resonance energies and widths
are reported for the screening parameter in the range 0.0-0.07 (in a0
-1), to the best our knowledge, for the first time in the literature. 相似文献
16.
S. Kar Y. K. Ho 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,48(2):157-165
We have investigated the bound states and resonance states of
plasma-embedded tdμ and ddμ molecular ions using accurate
correlated basis functions. The plasma effect has been taken care of by
considering the Debye shielding approach of plasma modeling which admits a
variety of plasma conditions. The density of resonance states are calculated
using the stabilization method. The ground and excited states energies, and
the S-wave resonance energies of tdμ and ddμ molecular ions
immersed in plasmas are reported for various shielding parameters, along
with the 1S and 2S threshold energies of the tμ and dμ atoms. 相似文献
17.
Mahdi Rezaei-Sameti 《Physica B: Condensed Matter》2012,407(1):22-26
In this work, an armchair model of the (4,4) boron phosphide nanotubes (BPNTs) with a 1-nm length and consisting of 32 B and 32 P atoms is considered to study the influence of doping three atoms of aluminum in sites of boron (B3AlPNTs) and three atoms of nitrogen in sites of phosphors (BP3NNTs) on the electrostatic structure properties. The mouths of nanotubes are capped by hydrogen atoms in order to saturate the dangling bonds of the boundaries and to decrease the calculation time. The structures of BPNTs, B3AlPNTs and BP3NNTs are optimized by performing the level of density functional theory (DFT) using 6-31G? basis set. The optimized structures are used for calculating the chemical shielding (CS) tensors and nuclear magnetic resonance parameters such as isotropic chemical shielding (CSI) and anisotropic chemical shielding (CSA). The results reveal that in both models of B3AlPNTs and BP3NNTs by doping N atoms the chemical shielding parameters of P and B atoms, which are directly connected to the Al and N atoms decreased and the other sites significantly changed. 相似文献
18.
CsCaF3 crystals doped with Yb3+ ions have been studied using the electron paramagnetic resonance and optical spectroscopy methods. Several types of paramagnetic Yb3+ centers were found, among which a paramagnetic center in the unusual position was established. The parameters of the corresponding spin Hamiltonians and schemes of the energy levels of the observed centers were determined. 相似文献
19.
A. I. Pegarkov 《Optics and Spectroscopy》2001,91(1):87-91
Within the framework of the nonadiabatic approach developed in the preceding paper, the resonance scattering, resonance Raman scattering, and resonance fluorescence are studied in detail for diatomic and triatomic molecules, and polyatomic symmetric and antisymmetric top molecules, which interact with the field of short-wavelength radiation with a wavelength λ ≥ Å and an intensity up to 1014 W/cm2. The coherent excitations of high-lying Rydberg and autoionizing states are taken into account. Analytical expressions for calculating the tensors and cross sections of the above processes are derived. 相似文献
20.
D. S. Chuchelov S. A. Zibrov V. V. Vasiliev A. V. Taichenachev V. I. Yudin V. L. Velichansky 《Bulletin of the Lebedev Physics Institute》2017,44(10):281-285
The study of the previously proposed method for improving the parameters of the coherent population trapping resonance on the 87Rb D1 line using two counterpropagating bichromatic fields with orthogonal circular polarizations is continued. The method consists in elimination of trap states existing in the conventional σ+ measurement scheme and limiting the resonance amplitude. The resonance parameters are studied in a wide range of pump radiation intensities and in various configurations implementing the σ+-σ? scheme. 相似文献