Scientific publications
Geh Wilson Ejuh
The African review of physics
The molecular structures of pyrimethamine and sulfadoxine have been explored for non linear optical ef fects. The abinitio Hartee Fock calculations and Density Functio nal Theory with B3LYP method have been carried out employing 6311++G** basis set. The dipole moments ( µ), polarizability ( α), and first hyperpolarizability ( βmol ) in gas phase and in solvated medium (water and ethanol) are calculated using the same level of theory. The variation of th e C-N bond lengths suggests that there is an extended pi-electron delo calization over the pyrimidine moiety that is respo nsible for non linearity of these molecules. Equally, the large values of βmol for these molecules suggest potential applications of these molecular systems in the development of non linear materials. The large βmol values, which is a measure of the non linear optical activity of the molecular system, is associated wit h the intermolecular charge transfer resulting from an electron cloud movement through the pi-electron delocalization. Hence theoretical determination of βmol is quite useful, both in the understanding of relationship between the molecular structure and non linear optical properties.
