Chemical bond analysis in the ten-electron series

This thesis presents briefly the application of quantum mechanics on systems of chemical interest, i.e., the field of quantum chemistry and computational chemistry. The molecules of the ten-electron series, hydrogen fluoride, water, ammonia, methane and neon, are taken as computational examples. Some applications of quantum chemistry are then shown on these systems, with emphasis on the nature of the molecular bonds. Conceptual methods of chemistry and theoretical chemistry for these systems are shown to be valid with some restrictions, as these interpretations does not represent physically measurable entities. The orbitals and orbital energies of neon is studied, the binding van der Waalsinteraction resulting in a Ne2 molecule is studied with a theoretical bond length of 3.23 Å and dissociation energy of 81.75 μEh. The equilibrium geometries of FH, H2O, NH3 and CH4 are studied and the strength and character of the bonds involved evaluated using bond order, dipole moment, Mulliken population analysis and Löwdin population analysis. The concept of electronegativity is studied in the context of electron transfer. Lastly, the barrier of inversion for NH3 is studied, with an obtained barrier height of 8.46 mEh and relatively constant electron transfer.