Studying structure around heavy metal cations

by Prof. Riccardo Spezia (PhD CNRS,LAMBE, Univ. d'Evry, France)

Wednesday 28 Oct 2009, 17:00 → 18:00 Europe/Rome

Aula Corbino (Dip. di Fisica - Edificio E. Fermi)

Understanding molecular organization around heavy metal cations - like transition metals, lanthanoids or actinoids - is of fundamental importance to address their chemical and biochemical reactivity. Depending on the cation nature and the ligand nature, classical or ab initio theories can be used. In last years we have studied hydration of different metals using molecular dynamics with both classical (CLMD) and DFT-based Car-Parrinello (CPMD) approaches being able to rationalize in terms of microscopic properties XAFS and IR experiments. Classical MD has to overcome the parametrization problem, but for a chemical series (the lanthanoid series) we were able, by using polarizable force field, to provide in a simple, physical, way a set of parameters that provide structural results in very good agreement with recent EXAFS data. Finally, we will discuss some physical justification that can be obtained analyzing electronic density by means of DFT-based dynamics and discuss some problems that can come when using DFT methods.