Describing the stress on an atom or group of atoms is not trivial, where complex molecular shapes and potential contacts in condensed phases would not be captured by the standard second-order stress/strain descriptors at the molecular level. An extension of this approach is a multipolar expansion for the molecular "pressure": P V a ⇒ m σm ⊙ εm , where the m terms are the mth order tensors of the stress and strain, written in traceless forms. The 0th order term is the pressure/volumetric strain term, and the 2nd order term captures the deviatoric contributions. The 1st order term is the gradient terms in stress and strain, which would be particularly relevant in dynamic loading scenarios, and the 3rd order terms would capture the strain gradients. Higher order terms would be required for contact descriptions between distorted molecules.