Computational Determination of Electron-Electron Repulsion and Binding Energy within the Atom

By Docia Atanda, Dorothy Haas

Faculty Mentor: Leanna Giancarlo


The atomic binding energy is the energy needed to pull away the innermost electrons in an atom away from the nucleus. The atomic binding energy is a value that takes into account the nuclear charge, electrons, and electrostatic interactions between the two. Using ChemCompute and GAMESS software, the binding energy can be found for any element with the n quantum number less than or equal to 5, as GAMESS software is not compatible with larger elements. The n quantum number is equivalent to the number of electron shells in an atom. The binding energies of the first five elements of column one on the periodic table and the first five elements of column two on the periodic table were computed. The minimum value of the binding energy was that of hydrogen, at -0.498 a.u., which is reasonable given there is only one electron interacting with only one proton. The largest computed binding energy was for strontium, at -3131.497 a.u., where the electrons in the innermost electron shell are being pulled by the 38 protons in the nucleus. The negative sign on these values is representative of the attractive forces between the electrons and nucleus of an atom. The increase in value of the binding energy as the number of electrons is increased is in line with the fact that there will be more electrostatic pull from the nucleus to the innermost electrons.


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