Thesis (M.Sc.)--Chulalongkorn University, 2000

The solvation structures of Li+ and Mg2+ in liquid ammonia have been investigated using the Metropolis Monte Carlo scheme. Including three-body correction functions. The systems under investigation contain one Li+ in 201 NH3 and one Mg2+ in 201 NH3. The three-body correction includes functions representing orientations the ammonia molecules. From the experimental density for pure liquid ammonia at 277 K and 1 atm of 0.690 g.cm-3, a periodic cubic volume of side length 20.99 A was constructed. The Li+ -NH3 and Mg2+ -NH3 three-body correction functions have been developed based on Hatree-Fock calculations with Dunning's double zeta plus polarizations (DZP) basis set. The simulations yielded the first shell coordination of six for both Li+ and Mg2+ systems. The results are in agreement with the previous work whose no molecular orientation was taken in to account. A clear and useful conclusion is that the orientation of the solvent molecules can be neglected from consideration, at least when dealing with structural properties of the solution