Intermolecular Potentials from the Iterated Stockholder Atoms Approach

Who: Alston Misquitta, Queen Mary University Of London
Friday, July 8, 2016 - 2:00pm
Eberly 325
University Drive, Pittsburgh, PA 15260

The Iterated Stockholder Atom (ISA) algorithm [1] is proving to be one of the most interesting methods for atoms‐in‐a‐molecule (AIM): it leads to a unique definition of the atoms which are guaranteed to be maximally spherical while allowing for the effects of charge movement as a result of chemical bonding. Through a basis‐space, or BS‐ISA, algorithm [2] we are able to calculate the ISA solution at the basis‐set limit, with well‐defined atomic densities, in particular, with well‐behaved, exponentially decaying tails. This method has proved pivotal in developing accurate models needed for intermolecular interaction. For example, the distributed multipole moments from the BS‐ISA method have been shown [2] to be faster convergent than the popular DMA approach. Recently, we have used the BS‐ISA method to model the repulsion anisotropy [3,4], the hardness parameters in the generalised Born‐Mayer short‐range terms, and the dispersion damping [5]; all non‐empirically. In this talk I will highlight some of these applications and provide directions where I think the BS‐ISA algorithm will be useful. 

[1]  T. C. Lillestolen and R. J. Wheatley, ''Atomic charge densities generated using an iterative stockholder procedure'', J. Chem. Phys. 131, 144101‐6 (2009). 

[2]  A. J. Misquitta A. J. Stone, and F. Fazeli,' 'Distributed Multipoles from a Robust Basis‐Space Implementation of the Iterated Stockholder Atoms Procedure'', J. Chem. Theory Comput., 10, 5405‐5418 (2014). 

[3]  A. J. Misquitta and A. J. Stone, ''Ab initio atom‐atom potentials using Cam CASP: Theory and application to multipole models for the pyridine dimer'', arXiv:1512.06150v3 

[4]  A. J. Misquitta and A. J. Stone, ''Ab initio atom‐atom potentials using Cam CASP: Many‐body potentials for the pyridine dimer'', arXiv:1512.06155v3 

[5]  M. J. Van Vleet, Al. J. Misquitta, A. J. Stone, and J.R. Schmidt, ''Beyond Born‐Mayer: Improved models for short‐range repulsion in ab initio force fields'', arXiv:1606.00734v1