Vibrational normal modes calculations of the α-L-Fucose molecule in the crystalline state

Abstract

The methods and techniques of molecular mechanics and dynamics are based on the knowledge of the empirical molecular energy. Because this energy is not known, an analytical form is sought. This function depends on the internal coordinates of the molecule and contains a number of related parameters which are determined by adjustmen. In this work, we seek to determine the vibrational normal modes of the α-L-Fucose molecule in the crystalline state from the modified Urey-Braley-Shimanoushi force field (mUBSFF)[1]. By using experimental vibrations of data (Raman and IR spectra) it is possible, with an appropriate potential energy function, to refine these parameters (e.g. the force constants) by normal coordinate analysis. This procedure is done until the agreement between calculated and observed frequencies is satisfactory.