Estudo da geometria da uréia por métodos ab initio e simulação computacional de líquidos

Abstract

Recebido em 3/1/01; aceito em 12/9/01 STUDIES OF UREA GEOMETRY BY MEANS OF AB INITIO METHODS AND COMPUTER SIMULATIONS OF LIQUIDS. A study was carried out on the urea geometries using ab initio calculation and Monte Carlo computational simulation of liquids. The ab initio calculated results showed that urea has a non-planar conformation in the gas phase in which the hydrogen atoms are out of the plane formed by the heavy atoms. Free energies associated to the rotation of the amino groups of urea in water were obtained using the Monte Carlo method in which the thermodynamic perturbation theory is implemented. The magnitude of the free energy obtained from this simulation did not permit us to conclude that urea is non-planar in water.