Hallo allerseits, ich moechte auf den folgenden Vortrag morgen von Herrn Schneider (TU Berlin) hinweisen. Beste Gruesse, Helmut Harbrecht. -------- Original Message -------- Subject: Sonderforschungsbereich 611 - SFB-Seminar am Freitag, 5. Dezember 2008 Date: Wed, 03 Dec 2008 13:08:08 +0100 From: Michael Laurien <laurien@wiener.iam.uni-bonn.de> To: Astrid Link <astrid.link@iam.uni-bonn.de> Einladung zu einem Vortrag im SFB-Seminar Freitag, 5. Dezember 2008 Wegelerstr. 6, Seminarraum 610 10.15 Uhr Prof. Dr. Reinhold Schneider, TU Berlin, spricht zum Thema The Projected Coupled Cluster Method - Existence and Convergence *Abstract: *The electronic Schroedinger equation plays a fundamental role in molcular physics. It describes the stationary nonrelativistic behaviour of an quantum mechanical N electron system in the electric field generated by the nuclei. The (Projected) Coupled Cluster Method has been developed for the numerical computation of the ground state energy and wave function. It provides a powerful tool for high accuracy electronic structure calculations. The present paper aims to provide a rigorous analytical treatment and convergence analysis of this method. If the discrete Hartree Fock solution is sufficiently good, the quasi-optimal convergence of the projected coupled cluster solution to the full CI solution is shown. Under reasonable assumptions also the convergence to the exact wave function can be shown in the Sobolev H1 norm. The error of the ground state energy computation is estimated by an Aubin Nitsche type approach. Although the Projected Coupled Cluster method is nonvariational it shares advantages with the Galerkin or CI method. In addition it provides size consistency, which is considered as a fundamental property in many particle quantum mechanics.