In a previous article, hereafter named as Paper I, we have showed a relationship between atomic correlation energy of neutral atoms with 2 < Z < 29 and Tsallis entropy. In this article, we generalize this relation showing the link between the atomic correlation energy and a general form of entropy obtained from deformed algebra. The results evidence the role of both q and D parameters of the general entropy, in terms of contribution of the long-range interactions in the correlation energy. The q and D values, obtained as best fit of the atomic correlation energies 2 < Z < 29, indicate that this general form of entropy reduces to the Tsallis one, reproducing well the trend of the correlation energy for low Z. Moreover, as a consequence of these values of the parameters, the state atomic wave function is more localized with respect to the wave function calculated in the limit of Shannon entropy. V C 2010 Wiley Periodicals, Inc. Int J Quantum Chem 111: [2390][2391][2392][2393][2394][2395][2396][2397] 2011 Key words: electron correlation; entropy; deformed algebra W ithin the many-electron theory of atoms, molecules, solids, and so forth, an important consequence of the electron-electron repulsion is the so-called electron-correlation. The energetic measure of the electron-correlation is the correlation energy, defined as the difference between the exact non relativistic total energy and the HartreeFock energy, E c ¼ E exp À E HF . This physical quantity is because of the impossibility to solve analytically the Schrödinger equation for a many-electron system, because of the electron-electron potential V ee . In the framework of the density functional theory (DFT), the simplest approximation for E c is given within the local spin density approximation (LSD):where qðrÞ ¼ q " ðrÞ þ q # ðrÞ is the electron density and e c ðq " ðrÞ; q # ðrÞÞ is the correlation energy per particle of an electron gas with uniform spin-densities q # ðrÞ and q " ðrÞ.