Project Details
Projekt
Development of a linear-scaling MP2 method for large molecules by rigorous integral criteria
Applicant
Professor Dr. Christian Ochsenfeld
Subject Area
Theoretical Chemistry: Electronic Structure, Dynamics, Simulation
Term
from 2005 to 2010
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 16501951
Electron-correlation and in particular dispersion-type effects are crucial for the quantum-chemical calculation of many molecular systems. However, the computational effort of even the simplest ab initio approach accounting for these effects —second-order Møller-Plesset perturbation theory (MP2) — scales with the fifth power of molecular size, which prohibits the application of conventional approaches to more than 50–100 atoms. Therefore, the reduction of the scaling is crucial. Although impressive progress has been made by several groups towards this goal, there has been so far no rigorous way of preselecting numerically significant contributions to the correlation energy, so that either ad-hoc assumptions influencing the accuracy were necessary or the prefactors of the computational effort have been too large. In our work, we have introduced the first rigorous upper bounds (multipole-based integral estimates; MBIE) which allow to preselect the significant contributions to the MP2 energy without further assumptions. In this way, the same accuracy and reliability as in conventional approaches is guaranteed, combined with the possibility to attain a linear-scaling computational behavior. Based on this idea, the main goal of the present research proposal is the development of a linear-scaling MP2 method, which allows for the reliable computation of MP2 energetics for molecules with 500-1000 and more atoms (without symmetry), so that dispersion-type interactions can be accounted for in large molecular systems.
DFG Programme
Priority Programmes
