SCFMO STUDIES OF SOME SELECTED HYDROGEN BONDED SYSTEMS

Abstract

This research consists of three chapters : Chapter 1: Is introduction, that includes three parts, literalure survey on acetylene and disilyne, the chemistry of ecited states and the him of the study.

the

Chapter II: The theoretical methods employed in this work iand

calculation of potential energy function associated with molecrlar I

conformations.

I Chapter III: Exhibits results and discussions of MNDO i calculation on acetylene and disilyne as one of selected hydrogen bortded

structures of carbon and silicon as two members of group four iJ the periodic table, for studying substituent, charge and spin multiplicity effect as well as the detailed conformational analysis.

The equilibrium geomelus of under study molecules are deteJined and it was found that in spite of carbon and silicon present in the Jame group but differe from each other in their ability to make hydrogen bonds and also in equilibrium geometries, but the substituent effects by flobne not change geometries of both acetylene and disilyne in ground state Jhich in fact different; also, in considering charge effects that the positive cJarge does not affect the geometries of acetylene but negative charge chdnges geometries.