Isoelectronic Series Of Atoms Research Articles

Sternheimer valence shielding and antishielding factors for several2pand3patoms and ions

The Sternheimer valence shielding and antishielding factor R has been calculated for the isoelectronic series of atoms in 2p 1 , 2p 2 , 2p 4 , 2p 5 , 3p 1 , 3p 4 , and 3p 5 electronic configurations by means of the uncoupled numerical Hartree-Fock method. A slightly larger shielding effect is observed for the 1 D state relative to the 3 P state for N − , O, and S. In the 2p 4 series, where N − is included, it is found that the mononegative ion is characterized by an R which is twice as large as that for the isoelectronic neutral atom. The general trends observed in the variation of R within an isoelectronic series are discussed.

Some potential‐energy relationships for isoelectronic atomic series

AbstractRelationships between the total energy E, the nuclear‐electronic attraction energy Vne, and the interelectronic repulsion energy Vee are derived for isoelectronic series of atoms and ions. Using these, it is possible to determine Vne and Vee for the members of such series from a knowledge of just their total energies. The method is applied to the ground and first excited states of the two‐electron series, and the ground states of the three‐ and four‐electron series, and the results are discussed.

Atomic Multiconfiguration Self-Consistent-Field Wavefunctions

The ground-state 1S wavefunctions of the atomic isoelectronic series with two and four electrons (Z = 1 – 8, and 3–8, respectively), were calculated using the MC–SCF method restricted to pair replacements. These calculations were to test and demonstrate how rapidly the configuration expansions of the MC–SCF wavefunctions converge. In the two-electron series, nine configurations were required to yield 97% of the correlation energy, while ten configurations accounted for 86% of the correlation energy in the four-electron series. The quality of the reported wavefunctions has been tested by computing the expectation values of several one- and two-electron operators. The results obtained agree in general satisfactorily (deviations of ∼1%) with values computed from more complex wavefunctions, indicating that the compact MC–SCF functions reported are indeed of high quality.

Constant Energy Differences in Atomic Structure

IN a recent article Dash1 has emphasized how three successive ionization potentials Ip, IP+1, Ip+2 in an isoelectronic series of atoms give a constant second difference which is equal to twice the Rydberg constant R divided by the square of the principal quantum number n of the electron being ionized, thus:

Correlation Energy for Atomic Systems

The correlation energies are estimated for the isoelectronic series of atoms with 2 to 10 electrons in the ground state and in the excited states of the lowest electronic configuration. The obtained values of the correlation energy point out clearly the importance of precorrelation energy, i.e., the energy difference between Hartree and Hartree—Fock energies, the quasi-additivity of 1s, 2s, 2-, ··· intra- and intershell correlation, the relative importance of spin-multiplicity correlation and total angular-momentum correlation, and the Z effects on correlation. The estimate of the correlation energy makes use of energy data for the relativistic energy: the accuracy of the relativistic energy computations is discussed. The 2 to 10 electron correlation energies were used as a basis to estimate the 11 to 18 electron correlation energies and to draw general conclusions on the value of the correlation energy for any atomic system.

Perturbation Energy Coefficients and Ionization Potentials of the Ground State of Three- to Ten-Electron Isoelectronic Atomic Series

Perturbation Energy Coefficients and Ionization Potentials of the Ground State of Three- to Ten-Electron Isoelectronic Atomic Series