Studies On The Properties Of Urea(H₂O)_n Clusters In Terms Of ABEEM/MM Fluctuating Charge Molecular Force Field

We present a new urea-water potential model based on the atom-bond electronegativity equalization fluctuating charge molecular force field (ABEEM/MM), which is a urea model in conjunction with the ABEEM-7P water model. The potential was applied to study the properties of Urea(H2O)n (n=1-3), including structures, dipole moments, ABEEM charge distributions, interaction energies, and hydrogen bonding cooperative effects, and so on. These results are in good agreement with the experimental and ab initio results. The larger urea-water clusters, Urea(H2O)n (n=4-8), are also studied to further test the reasonableness of this potential and the correctness and transferability of the parameters of the ABEEM/MM. The results also show good consistency with those of ab initio calculations.In terms of the atom-bond electronegativity equalizationσ-πmodel, i.e. ABEEMσ-πmodel, the charge distributions of some typical heterocyclic compounds containing nitrogen atom were studied. Results show very good consistency with the ab initio calculations, and this validates further the rationality and reliability of the ABEEMσ-πmodel.