The Role of the Lone Pairs in Hydrogen Bonding

Monday, February 5 11:45-13:15
Electron density and density matrix, a key quantity for systems
at and out of equilibrium.
Pierre BECKER, Jean Michel GILLET, Blandine COURCOT
Ecole Centrale Paris, Grande Voie des Vignes, 92295 Chatenay Malabry Cedex, France - SPMS CNRS
Unit, pierre.becker@ecp.fr
The crucial role of one particle reduced density matrices occurs when trying to get complementary
information from different sources of observation for steady state systems. Application to charge, spin
and momentum density analysis has been the main research activity of our group. Taking advantage
of the pioneering work by Vedene Smith and Wolf Weyrich, we were able to develop a ”pseudo-atomic,
pseudo-molecular or clusterëxpansion of the reduced density matrix. This is a generalisation to density
matrix of the celebrated pseudo-atomic expansion of the charge density. Each term takes into account the
interaction with neighboring sites. Transferability is an implied concept to be discussed. Applications
go from solids to molecules in interaction with their surrounding medium. We were able to jointly
analyze Bragg and Compton scattering experiments. A recent generalization to pharmaceuticals and
their interaction with biological medium is considered. Finally first steps for an approach of systems out
of equilibrium and undergoing chemical reactions are discussed.
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