  We present the extension of the SIBFA (Sum of Interactions Between Fragments
Ab initio Computed many-body polarizable force field to condensed phase
Molecular Dynamics (MD) simulations. The Quantum-Inspired SIBFA procedure is
grounded on simplified integrals obtained from localized molecular orbital
theory and achieves full separability of its intermolecular potential. It
embodies long-range multipolar electrostatics (up to quadrupole) coupled to a
short-range penetration correction (up to charge-quadrupole),
exchange-repulsion, many-body polarization, many-body charge
transfer/delocalization, exchange-dispersion and dispersion (up to C10). This
enables the reproduction of all energy contributions of ab initio
Symmetry-Adapted Perturbation Theory (SAPT(DFT)) gas phase reference
computations. The SIBFA approach has been integrated within the Tinker-HP
massively parallel MD package. To do so all SIBFA energy gradients have been
derived and the approach has been extended to enable periodic boundary
conditions simulations using Smooth Particle Mesh Ewald. This novel
implementation also notably includes a computationally tractable simplification
of the many-body charge transfer/delocalization contribution. As a proof of
concept, we perform a first computational experiment defining a water model
fitted on a limited set of (SAPT(DFT)) data. SIBFA is shown to enable a
satisfactory reproduction of both gas phase energetic contributions and
condensed phase properties highlighting the importance of its
physically-motivated functional form.
