An ab initio study of structure and stability of Al2F2 molecule

Possible isomers of Al2F2 molecule are shown to exist by ab initio molecula r orbital calculations at UMP2/6 - 311G(d) level. The values of energy at U MP2/6 - 311G(d) and UQCISD(T)/6 - 311 + G (3df)// UMP2/6 - 311G(d) level of the theory show that the isomer that has D-2h symmetry and (1)A(g) electro nic state is the most stable equilibrium geometry. In the isomer, the Al-F bond length is 0.19074 nm, and the bond angles Al-F-Al and F-Al-F are 104.6 2 degrees and 75.38 degrees, respectively. Two strong vibrations have been found at 441.27 cm(-1) and 401.93 cm(-1). These results are in agreement wi th experimental ones. Analyses of electronic structure show that the active positions are on the Al atoms, and are main additive areas where it reacts with other compounds. The dimerization energies at UMP2/6 - 311G(d) and UQ CISD(T)/6 311 + G(3df)//UMP2/6 - 311G(d) levels are - 75.01 kJ/mol and - 66 .13 kJ/mol, respectively, and are in agreement with those in the literature . The results show that the dimerization of AlF is thermodynamically favore d.