Abstract

Quantum  Chemical  Topology  (QCT) [1]  is  a  method [2] that  partitions  the  electron  density  into  so‐called topological  atoms,  using  the  insights  of  dynamical systems.  As  an  example,  the  figure at top right shows how glycine is  partitioned into topological atoms. There are no gaps between these atoms and they do not  overlap.  Each atom is a box with a particular shape and a finite volume. If the coordinates change then the shapes of the atoms change too, as well as their multipole  moments. This  complex  relationship  is captured by machine learning. Topological atoms can be regarded as macroscopic objects, malleable yet open systems.    

In this talk I will explore how these ideas can be used toenhance the  realism of the electrostatic energy a protein force field [3], including polarisation and charge transfer.

[1] (a) Popelier, P.L.A.; Bremond,E.A.G. Int.J.Quant.Chem. 2009, 109, 2542. (b) Popelier, P.L. A.; Aicken, F. M. Chem. Phys. Chem. 2003,4, 824. (c) Popelier, P. L. A. Quantum Chemical Topology: on Bonds and Potentials; Springer: Heidelberg, Germany, 2005.

[2] (a) Bader, R. F. W. Atoms in Molecules. A Quantum Theor. ; Oxford Univ. Press, 1990. (b) Popelier, P. Atoms in Molecules. An Introduction; Pearson Education: London, 2000.

[3] Mills, M. J.L.; Popelier, P. L. A.Theor.Chem.Acc. 2012, 131, 1137.