A New Parameterization of an All-Atom Force Field for Cellulose

We have parametrized an AMBER force field in a TEAMFF database to accurately represent intra- and intermolecular interactions of cellulose. Parameters are obtained by fitting quantum mechanics (QM) energetic data on a training set of 12 simple and substituted heterocycles, alcohols, ethers, and saccharides. The temperature-dependent Lennard–Jones parameters were optimized by fitting experimental data of 23 molecular liquids at different temperatures using molecular dynamics (MD) simulations. Validation on cellobiose, the monomer of cellulose, exhibits excellent agreement between the data obtained by molecular mechanics calculations using the present force field and QM calculations in terms of conformational energies, structures, and vibrational frequencies. The MD simulation results of cellulose Iβ crystal agree well with the experimental data, showing a 0.1% deviation in density and less than 1% deviations in all the cell parameters.