Developing a force field for simulation of poly(ethylene oxide) based upon ab initio calculations of 1,2-dimethoxyethane

The relative conformational energies in the 1,2-dimethoxyethane (DME) molecule have been extensively studied using B3LYP and MP2 ab initio methods, employing a range of commonly used basis sets. These conformational energies have been used to fit new O-C-C-O and C-O-C-C torsional interaction parameters for the OPLS-AA force field. The resulting force field (DMEFF) shows some improvement in conformational populations, calculated from molecular dynamics simulation of bulk DME, compared to two other commonly used force fields. Extensive reverse-engineering of the OPLS-AA energy function has also allowed the development of additional sets of torsion parameters for these two dihedral types, resulting in a force field that reproduces the conformational behaviour of DME in the liquid phase extremely well.