Ab initio investigation of isomerism, structure and stability of dimer molecules of (LiMgH3)2 and (LiMgF3)2salts and their fragments

Ab initio calculations of potential energy surfaces in neighborhood of key structures of non rigid dimer molecules of lithium salts of (LiMgX3)2 and binuclear anions Mg2X5-, dianions MgX62- and molecules Mg2X4 (X=H, F) are done in the framework of QCI-SD(T)/6-31(+)G**//MP2/6-31G* + ZPE(MP2/6-31G*) and MP2/6-31G*//HF/6-31G* + ZPE(HF/6-31G*) approximations. Equilibrium geometric parameters, relative energy and energy of decomposition of isomers, frequencies and IR-intensities of normal vibrations are determined. Data obtained are compared with results of analogous calculations for beryllium related compounds