The impact of a highly charged ion onto solid gives rise to charge exchange between the and target atoms, so that slow gets neutralized in vicinity surface. Using Ar Xe ions surface-only material graphene as target, we show neutralization deexcitation proceeds on sub-10 fs time scale. We further demonstrate multiple Interatomic Coulombic Decay (ICD) model can describe observed ultrafast deexcitation. Other mechanisms involving nonradiative decay quasimolecular orbital formation during are...

A comparison is made of the accuracy with which total electronic energy can be calculated by using either finite basis set approach (the algebraic approximation) or difference methods in calculations Hartree-Fock model for ground (X1 Sigma +) state carbon monosulphide molecule. The CS molecule considered as a prototype systems containing atoms from different rows periodic table. convergence carried out within approximation monitored employing systematically constructed sets increasing size....

The Hartree-Fock ground state potential energy curve for the carbon monoxide molecule is calculated using both finite difference and basis set methods. results of calculations performed at ten internuclear separations are reported a comparision made curves over range separations, 1.970-2.330 a0, around experimental equilibrium value. Potential constants spectroscopic determined.

A comparison is made of the accuracy with which total electronic energy can be calculated by using either finite basis set approach (the algebraic approximation) or difference methods in calculations Hartree-Fock model for ground (X1Σ+) states Group IIIb fluorides: boron fluoride, aluminium fluoride and gallium molecules. The XF molecules, X = B, Al, Ga, are considered as a prototype systems containing increasingly heavy atoms numbers electrons. convergence carried out within approximation...

The accuracy of the total energies obtained for series 14 electron molecules N2, CO, BF, NO+ and CN- by means matrix Hartree-Fock calculations using a universal basis set Gaussian-type functions is reaccessed in light improved finite difference calculations.

A comparison is made of the accuracy with which electric moments \ensuremath{\mu}, \ensuremath{\Theta}, \ensuremath{\Omega}, and \ensuremath{\Phi} can be calculated by using finite basis set approach (the algebraic approximation) finite-difference method in calculations employing Hartree-Fock model for ground states 16 diatomic molecules at their experimental equilibrium geometries. Specifically, ${2}^{n}$-pole $n=1,2,3,4,$ ${\mathrm{N}}_{2},$ CO, BF,...

Abstract A comparative study of quasirelativistic equations used in atomic structure calculations has been performed. uniform derivation all the is presented, and some their specific features are discussed detail. Electron density distributions, orbital energies, expectation values r n obtained with different methods compared ones resulting from Schrödinger Dirac equations. The most accurate found to be Wood Boring Barthelat, Pelissier, Durand. (They reproduce almost exactly electron...

Recently it has been demonstrated that the finite difference Hartree-Fock method can be used to deliver highly accurate values of electric multipole moments together with polarizabilities ${\ensuremath{\alpha}}_{zz},{A}_{z,zz}$, and hyperpolarizabilities ${\ensuremath{\beta}}_{zzz}$, ${\ensuremath{\gamma}}_{zzz},{B}_{zz,zz}$, for ground states various atomic diatomic systems. Since these results regarded as de facto limit their quality is utmost importance. This paper reexamines use field...

A comparison is made of the accuracy by which electric dipole polarizability αzz and hyperpolarizability βzzz can be calculated using finite basis set approach (the algebraic approximation) difference method in calculations employing Hartree-Fock model. The numerical methods were tested on ground states H2, LiH, BH FH molecules at their respective experimental equilibrium geometries. For molecule its geometry, a sequence distributed universal even-tempered sets have been used to explore...

Recurrence formulae determining radial matrix elements of rq between quasirelativistic hydrogenic wavefunctions are derived. In the diagonal case they a generalisation well known Kramer's relations. The also transformed to basis Dirac wavefunctions.

Abstract A transformation decoupling the Dirac second‐order equations for large and small components of radial atomic wavefunction has been derived. The procedure is exact one‐electron atoms approximate, though very accurate, a general case an spherical potential. Its connection with quasirelativistic theory discussed. applied to deriving optimized equation establishing relations between wavefunctions. Formulas resulting from these considerations allow improvement expectation values...

We investigate the accuracy with which electric dipole polarizability, αzz, and hyperpolarizability, βzzz, can be calculated by using algebraic approximation, i.e. finite basis set expansions, means of difference method in calculations for ground states 14 electron systems N2, CO BF within Hartree–Fock model at their respective experimental equilibrium geometries. For a well-chosen grid, technique provide energy moment expectation values approaching machine precision used to assess...

In the present study we have investigated three-photon ionization in Ca which autoionizing states are engaged. The two-photon resonant process (from ground state 4s2 1S0) occurred through or at least vicinity of one following states: 4s4d 1D2, 4p2 3P2, 4s6s 1S0, 1D2 and with third photon either reaching continuum directly states. transitions to 3dmp, mf: 1P1, 3P1 3D1 for m up 21 been observed. Some resonances found had not observed before a high-resolution one-photon absorption experiment...

A comparison is made of the finite basis set approach (the algebraic approximation) and difference methods in calculations using Hartree-Fock model for ground (X1Σ+) states heaviest Group IIIb fluorides: indium fluoride thallium molecules. The XF molecules, X = In, Tl, are considered as a prototype systems containing increasingly heavy atoms number electrons. New GaF state improve upon earlier results. convergence carried out within approximation monitored by employing systematically...

The two- and three-photon resonant ionization of Ca has been studied. Calcium atoms in the thermal atomic beam were ionized from ground state by absorption. ion signals exhibited resonances attributed to two-photon transition transitions due , autoionizing states. A simple theoretical model was used reproduce main features observed spectra ionization.

Within the Hartree–Fock approximation, distributed basis sets of s-type Gaussian functions are used to compute those portions ground-state potential energy curves H2, LiH and BH molecules for which model is appropriate. The exponents generated using even-tempered prescription an anharmonic employed distribute functions. For few-electron diatomic systems, this approach known support sub-μHartree accuracy electronic energies. studied in present work, matrix expectation values compared with...

In order to improve the theoretical reproduction of splitting energy levels for S-state f electron ions, a model in which relativistic effects are included an effective way is used. Although operators act within spin-orbital space, and radial integrals involve large small components theory, all required matrix elements evaluated intermediate coupling scheme. The approach illustrated by results numerical calculations performed representative ions: Gd3+, Cm3+, Bk4+. analysis support...

In a previous paper, we have made comparison of the accuracy with which electric dipole polarizability αzz and hyperpolarizability βzzz can be calculated by using either finite basis set approach (the algebraic approximation) or difference method in calculations for ground states H2, LiH, BH FH molecules, at their respective experimental equilibrium geometries, within Hartree–Fock model. A re-examination molecule shows it to very sensitive both choice grid employed calculation construction...