Related papers: Study of quadrupole polarizabilities with combined…
The coupled-channel technique augments a non-relativistic distorted wave born approximation scattering calculation to include a coupling to virtual states from the negative energy region. It has been found to be important in low energy…
The dynamic dipole polarizabilities for the Li atom and the Be+ ion in the 2s and 2p states are calculated using the variational method with a Hylleraas basis. The present polarizabilities represent the definitive values in the…
In this work, we propose new field-free estimators for static field-gradient polarizabilities in finite temperature PIMC simulation. Namely, dipole--quadrupole polarizability $A$, dipole--dipole--quadrupole polarizability $B$ and…
Searching for an accurate optical clock which can serve as a better time standard than the present day atomic clock is highly demanding from several areas of science and technology. Several attempts have been made to built more accurate…
We investigate the role of the electron correlation effects in the calculations of the electric dipole polarizabilities (\alpha) of elements belonging to three different groups of periodic table. To understand the propagation of the…
In this paper I propose a new model for representing the formation energies of multicomponent crystalline alloys as a function of atom types. In the cases when displacements of atoms from their equilibrium positions are not large, the…
This paper presents an approach for obtaining accurate interaction energies at the DFT level for systems where dispersion interactions are important. This approach combines Becke and Johnson's [J. Chem. Phys. 127, 154108 (2007)] method for…
A new method of computing multipolar exchange interaction in spin-orbit coupled systems is developed using multipolar tensor expansion of the density matrix in LDA+U electronic structure calculation. Within mean-field approximation,…
We formulate a parity-mixed coupled-cluster (PM-CC) approach for high-precision calculations of parity non-conserving amplitudes in mono-valent atoms. Compared to the conventional formalism which uses parity-proper (PP) one-electron…
The Configuration Interaction (CI) method using orbitals centered on the nucleus has recently been applied to calculate the interactions of positrons interacting with atoms. Computational investigations of the convergence properties of…
We calculate (g-2) of the muon and the QED coupling alpha(M_Z^2), by improving the determination of the hadronic vacuum polarization contributions and their uncertainties. We include the recently re-analysed CMD-2 data on e^+e^- -> pi^+…
Novel equations for the electric dipole polarizability $\alpha_{_{E1}}$ of low-lying excited states in atomic nuclei -- and the related $(-2)$ moment of the total photo-absorption cross section, $\sigma_{_{-2}}$ -- are inferred in terms of…
The fully retarded dispersion interaction between an atom and a cluster or between two clusters is calculated. Results obtained with two different methods are compared. One is to consider a cluster as a collection of many atoms and evaluate…
We report a new technique to determine the van der Waals coeffcients of lithium (Li) atoms based on the relativistic coupled-cluster theory. These quantities are determined using the imaginary parts of the scalar dipole and quadrupole…
The long-range quadrupole-quadrupole ($\sim R^{-5}$) and leading dispersion ($\sim R^{-6}$) interactions between all pairs of excited Hg($6s6p$) $^3P_0$, $^3P_1$, $^3P_2$, and $^1P_1$ atoms are determined. The quadrupole moments are…
We have carried out a detailed and systematic study of the correlation energies of inert gas atoms Ne, Ar, Kr and Xe using relativistic many-body perturbation theory and relativistic coupled-cluster theory. In the relativistic…
An implementation of the coupled-cluster single- and double excitations (CCSD) method on two-dimensional quantum dots is presented. Advantages and limitations are studied through comparison with other high accuracy approaches for two to…
Determination of nuclear moments for many nuclei relies on the computation of hyperfine constants, with theoretical uncertainties directly affecting the resulting uncertainties of the nuclear moments. In this work we improve the precision…
A practical high-accuracy relativistic method of atomic structure calculations for univalent atoms is presented. The method is rooted in the coupled-cluster formalism and includes non-perturbative treatment of single and double excitations…
The combination of the configuration interaction method and all-order single-double coupled-cluster technique is used to calculate excitation energies, ionization potentials and static dipole polarizabilities of superheavy elements…