> regarding the reduction of 1s electron density at Be nucleus > due to the compression.
I think that such a behavior is not against the nature. When Be is compressed, inner levels of neighboring atoms start to overlap in a more extent, the interaction changes profile of 1s radial function - spreads it. Why not? By the way, I have looked through my old calculations under hands with changing the lattice parameter and found that, for other elements, inner levels behave the same way, also (Fe, Al, Ga) - the core contribution to density decreases with compression, unlike the valence contribution and the sum of them. Best regards Lyudmila Dobysheva ------------------------------------------------------------------ Phys.-Techn. Institute of Ural Br. of Russian Ac. of Sci. 426001 Izhevsk, ul.Kirova 132 RUSSIA ------------------------------------------------------------------ Tel.:7(3412) 442118 (home), 218988(office), 250614(Fax) E-mail: lyu at otf.fti.udmurtia.su, lyu at otf.pti.udm.ru, lyuka17 at mail.ru http://fti.udm.ru/content/view/25/103/lang,english/ ------------------------------------------------------------------