A study of electron density distribution in each individual electronic ahell for Be-atom by using roothaan hartree fock wave function.

The partitioning technique has been used to analyze (1s² 2s²) ground state of Beatom for six-pairs electronic wave functions, two of these are for the Intrashells and the rest for inter-shells by using Roothaan-Iartree-Fock wave function published by Bunge et al [73]. The aim of this research is to snidy the tlieoretical properties of Be-atom in the (1s² 2s²) state, a discussion between the intra- and inter-sheel in the position space has been compared with results that obtined in the momentum space, is given. At the same time all these results were compared that are calculated by other works, by using the partitioning technique. The properties particle that studied in this work for the position and momentum space are: 1.The one- density distribution D(r), I(p). The two-particle density distribution D(r.r2), I(p,p2).3. The inter-electronic distribution function f(r12),f(p12). 4. The partial distribution function g(r12 r), g(p12,p). 5.The Expectation values , ,

and where -2. These parameters are very important in the studying of the physical and chemical properties of the atoms, and for this purpose; a computer program was designed in Quick Basic, Fortran and Mathcad compilers to calculate tliese parameters for the Be-atom.