Intershell interaction

Let us start with the one-electron operators. Their intershell matrix elements are small or vanish. Therefore, the total matrix element of such an operator is simply equal to the sum of corresponding quantities describing that interaction within each shell. Thus, for operators T and P (1.15) we have ... 

The analysis of the d spectra is more complicated than for pN due to intershell interactions and will not be discussed further here. 

Many-body theory has also been applied to calculate the response of negative ions [253], where intershell interactions and core rearrangement effects are even greater than for neutral atoms. It turns out that the spectra of photodetachment in negative ions are dominated by correlation effects to an even greater degree than photoionisation for neutral atoms. 

The distortion effect is automatically included in a Hartree-Fock calciUation based on SCF MO s for the composite S) tem of the interacting atoms. Ransil s "best limited H.F. SCF MO calculation gave the He He interaction wdl, aroimd the minimum (r,), but gave too little attraction at (r/r,) larger than about 1.2. The attraction at large r is an intershell correlation effect. This effect has been hitherto treated by the theory of London dispersion forces and applied also to the non-bonded attractions between different parts of a saturated molecule to obtain heats of formation and isomerization. ... 

It is obvious that more sophisticated relativistic many-body methods should be used for correct treating the NEET effect. Really, the nuclear wave functions have the many-body character (usually, the nuclear matrix elements are parameterized according to the empirical data). The correct treating of the electron subsystem processes requires an account of the relativistic, exchange-correlation, and nuclear effects. Really, the nuclear excitation occurs by electron transition from the M shell to the K shell. So, there is the electron-hole interaction, and it is of a great importance a correct account for the many-body correlation effects, including the intershell correlations, the post-act interaction of removing electron and hole. 

Melting of 2D clusters of up to 80 dipoles, interacting with a 1/r potential, confined by a quadratic potential has been determined by means of MC simulations by Belousov and Lozovik [191]. Melting of the smaller clusters (size N < 37) differs from that of the larger ones through an additional stage characterized by orientational intershell disordering of pairs of shells. 

The agreement may be restored, only if one takes into account the variation of intershell interaction, which becomes different from pure Coulomb V due to connection with the same states, which lead to F<1. Let us estimate the variation of interaction near threshold where the relation holds. Denoting the... 

The correction of intershell interaction affects some other characteristics e.g. (See Fig. 2), where the preservation of... 

The first summation in (6.6.10) represents the energy of the shell- C electrons alone in the field of the nuclei the double sum contains the intershell coulomb-exchange interactions with other shells. The averaging used gives equal weight to all the states that can be formed by linear combination of determinants in which a fixed number ri/c of electrons is assigned to each set of 2mj( spin-orbitals. 

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