Structural investigation of liquid acetic acid by neutron scattering, DFT calculations and molecular dynamics simulations. Complementarity to x-ray scattering results

Neutron scattering experiments have been performed on fully deuterated liquid acetic acid (AA) at room temperature and atmospheric pressure. The scattering data are analyzed to yield the structure factor SM(Q), the molecular form factor F1(Q) and the pair correlation function g(r). To describe the intermolecular arrangement of the liquid, we have considered two dimers and two trimers, involving the isomer cis, already described in our x-ray scattering study. Neutron scattering data show that the local order of the liquid is well described by linear and ring cis trimers. Complementarity with recent x-ray results is then highlighted. Using four force fields, MD simulations show that x-ray and neutron scattering data are better reproduced by both OPLS-AA1 and OPLS-AA2 potentials.