<i><span style="font-size:14.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:black;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">Ab-initio </span></i><span style="font-size:14.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:black;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">molecular orbital calculations on group <b>III </b>elements and their halides</span>

Abstract

The effect of halogenation of dimeric hydrides of boron, aluminium and gallium is studied theoretically for the first time. <i>Ab-initio </i>molecular orbital theory at the RHF/6-31G* level has been used to investigate the physico-chemical properties of the dimers of hexahydrides and halogen substituted hexahydrides. The total energy, ionization potential, charge density and dipole moments are calculated. Halogenation of the dimmeric hydrides of Group IIIA elements brings out some interesting properties of the electronic structure of these molecules. From the calculation of ionization potential, it is seen that substitution by bromine decreases the ionization potential. The calculation also shows that whenever substitution of halogen occurs at the bridge position, the ionization potential is further lowered. From the charge density calculation, it is observed that the introduction of halogen (F, Cl or Sr) atoms alters the entire charge distribution. Aluminium halides have stable structures and charge distribution compared to other halides of Group III elements. If the bridge atoms are not halogenated gallium behaves more or less like aluminium in all respects. A possibility of existence of dimers of gallium halides is explored. The dipole moments of the molecules are calculated and reported.