University of Pittsburgh

Daniel S. Lambrecht

Contact Info:

Department of Chemistry
Chevron Science Center
219 Parkman Avenue
Pittsburgh, PA 15260

Office: 322 Eberly Hall
Phone: 412-624-8912

Assistant Professor

Theoretical and Computational Chemistry; Reduced Scaling and Efficient Approaches; Computational Catalysis

The Lambrecht lab develops and applies novel computational approaches to describe “real chemistry” at the electronic structure level. Our main goals are (i) to push the boundaries of what is technically feasible to larger and more complex systems, thus allowing more realistic simulations, (ii) to gain a detailed understanding of chemistry at the electronic structure level, and (iii) to develop rationales for tailor-making molecular systems with specific chemical properties. A particular emphasis is placed on collaboration with experimental partners to devise novel catalysts and materials for energy applications.

Reduced-Scaling Approaches

We aim to enable calculations on larger systems than conventionally possible, which allows for more realistic chemical models. Examples developed in the lab are in the fields of Møller-Plesset perturbation theory to second order (MP2) and double hybrid density functional theory (DHDF), which are the cheapest methods that incorporate van-der-Waals interactions at an electronic structure level. While conventional implementations are typically limited to on the order of 100 atoms due to a computational scaling proportional to N5 (where N is the system size), we developed linear-scaling variants that extend the applicability to more than 1,000 atoms - the largest application so far being a 1,600 atom RNA ribozyme molecule. The scaling reduction is achieved by screening approaches exploiting the fact that some interactions between electrons (such as dispersion or vdW forces) are short-ranged and can therefore be neglected if the distance is big enough. Other approaches developed in the lab involve sparse matrix techniques, multi-scale approaches, as well as tensor decompositions.

Computational Catalysis

Chemical reactivity and catalysis are intimately linked to changes in the molecular electronic structure. It is therefore not surprising that electronic structure theory can make valuable contributions to the understanding of catalytic cycles and ultimately the rational design of improved catalysts. We develop electronic structure and embedding methods that yield an accurate and computationally feasible description of chemical reactions in solvent or solid environments. In cooperation with experiment we aim at gaining insights into the thermodynamics, kinetics and spectral signatures along catalytic pathways. Another focus is to provide rationales for the improvement of catalysts. Here we are working on decomposition methods that allow us to extract correlations between electronic structure descriptors for ligands and solvents and thus ultimately allow to make recommendations for more active catalyst systems.

Awards

  • Award for best PhD in Chemistry & Pharmacy, 2007

    Kekulé PhD Fellowship, 2005-2007

    Baden-Württemberg PhD Scholarship, 2003-2005

    German Academic Exchange Service Fellowship at UNC-Chapel Hill, 2001-2002

Publications

Linear‐Scaling Methods in Quantum Chemistry,” C. Ochsenfeld, J. Kussmann, and D. S. Lambrecht, Reviews in Computational Chemistry , Vol. 23, 2007, Pages 1-82, http://media.wiley.com/product_data/excerpt/11/04700820/0470082011.pdf
Rigorous integral screening for electron correlation methods,” D. S. Lambrecht, B. Doser, and C. Ochsenfeld, J. Chem. Phys., Vol. 123, 2005, Pages 184102 ,
A kinetic energy fitting metric for resolution of the identity second-order Møller-Plesset perturbation theory,” Daniel S. Lambrecht, Kai Brandhorst, William H. Miller, C. William McCurdy, and Martin Head-Gordon, J. Phys. Chem. A, Vol. 115, 2011, Pages 2794 ,
Higher order singular value decomposition in quantum chemistry,” Franziska Bell, Daniel S. Lambrecht, and Martin Head-Gordon, Mol. Phys., Vol. 108, 2010, Pages 2759 ,
Current Status of the AMOEBA Polarizable Force Field,” J. W. Ponder, C. Wu, P. Ren, V. S. Pande, J. D. Chodera, M. J. Schnieders, I. Haque, D. L. Mobley, D. S. Lambrecht, R. A. Di Stasio, M. Head-Gordon, G. N. I. Clark, M. E. Johnson, and T. Head-Gordon, J. Phys. Chem. B, Vol. 114, 2010, Pages 2549,
Simulated photoelectron spectra of CN-(H2O) via quasiclassical molecular dynamics,” Daniel S. Lambrecht, Gary N. I. Clark, Teresa Head-Gordon, and Martin Head-Gordon, J. Phys. Chem. A, Vol. 115, 2011, Pages 5928,
Charge-transfer and the hydrogen bond: Spectroscopic and structural implications from electronic structure calculations,” E. Ramos-Cordoba, D. S. Lambrecht, and M. Head-Gordon, Faraday Discussions, Vol. 150, 2011, Pages 345 ,