Localized orbitals for the treatment of dynamical and non-dynamical correlation

Линиите свързват координатора с партньорите.

Накратко на български

Цел на проекта

This project covers two principal points. The first point is about a variational method for obtaining localized orbitals. This approach has been recently proposed and implemented in a preliminary way in the Laboratoire de Physique Quantique (LPQ) of Toulouse University. Working with local orbitals induces a hierarchy in the importance of the Slater determinants in a large CI basis. This makes possible to eliminate those determinants whose weight in the CAS wave function is negligible, and to replace therefore the CAS expansion by a (usually much shorter) MR expansion. Part of the work will be to replace the variational approach with a perturbative one, the implementation of a reduced transformation of the two-electron molecular integrals and the possibility of neglecting the interaction between distant regions of the system. A second point is the application of this technique in the calculation of realistic systems covering different fields. In some electronic spectroscopy problem a local approach can produce important results. For example, in excitation processes of a cromophore group in a large molecule with a MR description of the orbitals located in the cromophore region, or in large delocalized biological systems ( e.g., the pi/pi* excitation in retinal). It is crucial to test the sensitivity of local approaches to far substituents shifts. In the study of the mixed-valence and magnetic systems the local descriptions are easier to interpret in accord to magnetic hamiltonians so that both the exchange and Coulomb parameters will be easier to get.

Оригинален текст от CORDIS (на английски).

Участници

• UNIVERSITE PAUL SABATIER DE TOULOUSE III · TOULOUSEКоординаторФранция

Връзки

• Виж в CORDIS