الفهرس 
introductionOnly 14 pages are availabe for public view
 |  | from | 242 |  |  |
| | | from | 242 | | |
Abstract
The importance of the fi ve membered heterocyclic compounds in the different life activities has initiated us to propose the subject of this thesis. The main concern in this thesis is the quantitative study of the vibrational spectra of the mol ecul es: cyc lopentad iene, furan, tlliophene, pyrrole and tetrahydrofuran. The infrared spectra of these concerned compounds in their liquid standard stat es in the region 3550 - 150 cl11-1 were measured The Laser Raman spectra of these molecules were measured and the different depolarization ratios of the observed bands were determined. The molecular structure and Geometry of the different molecules were theoretically determined by carrying out a geometlY optimization process using the MINDO!3 molecular orbital method . The ca lculated data were compared with those experimentally reported. The molecu les of all these compounds were fOlmd to ha ve a ring planar structure and belong to the C2v point group. The nonnal coordinates of the molecule were analysed, based on the group theoretical ru les, and the fundamental modes of vibration which belong to the different symmetlY irre lucibJe representations of the C2v po lilt group were deternlined. The symmetry coordinates for the different molecul es were constructed based on symmetry adapted linear combinations of the cartesian coordinate displacements. Using the molecular geometry (as cartesian coordinates), and the molecul ar synU11etry (as symmetry coordinates).