|Speaker :||Jozef Noga
Institute of Inorganic Chemistry
Slovak Academy of Sciences, Bratislava and
Department of Physical and Theoretical Chemistry
Faculty of Science, Comenius University, Bratislava
high precision calculations of molecular energies and properties
via explicitly correlated coupled cluster theory
|Date :||January 14, 2007|
|Time :||11.15 AM|
|Venue :||C V Raman Hall, IACS|
All are cordially invited to attend.
Abstract: One of the major difficulties with ab initio quantum chemical calculations based on the expansion of the wave function in terms of the one-particle basis is hidden in the fact that with inclusion of higher and higher angular momenta such expansions converge very slowly to the exact limits. The slow convergence is related to a wrong description of the wave function for coalescence of two electrons, known as dynamical electron correlation. This defect can be eliminated by an explicit incorporation of the interelectronic coordinate into the wave function expansion. R12/F12 theories for treating the dynamical electron correlation are discussed, and, in particular the explicitly correlated R12/F12 coupled cluster theory is introduced and its performance in different fields of chemical interest is shown.