Yannick Lemke

	Yannick Lemke, M.Sc., PhD student
	Room:	BZ5.014
	Phone:	+49 89 2180-72409
	E-Mail:	yannick.lemkecup.uni-muenchen.de

Research interests:

My current research efforts are centered around the variational relaxation of electronically excited states by means of constrained density functional theory (cDFT). With our recently developed Constraint-Based Orbital-Optimized Excited State Method (COOX), we are able to obtain excited states with arbitrary excitation patterns – including states with significant double-excitation character – at the density functional theory level with high algorithmic stability. The adherance to an Aufbau principle enables the straightforward computation of molecular gradients and enables the application of a large portion of the typical ground-state toolkit, e.g., electron correlation methods such as MP2, RPA, or σ-functionals. As such, COOX opens the door to a plethora of potential applications, such as the ab initio simulation of X-ray absorption spectra, excited states in complex molecular or bulk environments (e.g., explicit solvents), two-photon-two-electron excitations, and many more.

Previous works include the benchmarking and development of new σ-functionals, an RPA-based class of electron correlation method first proposed by Görling and co-workers, as well as the development and implementation of efficient algorithms for one-body reduced density matrix functional theory (RDMFT) for the description of strongly correlated systems.

Publications:

8	Y. Lemke, C. Ochsenfeld, "Top-Down Versus Bottom-Up Approaches for σ-Functionals Based on the Approximate Exchange Kernel", J. Phys. Chem. A 129, 774–787 (2025). (Trygve Helgaker Festschrift, special issue)
7	Y. Lemke, J. Kussmann, C. Ochsenfeld, "Highly Accurate and Robust Constraint-Based Orbital-Optimized Core Excitations", J. Phys. Chem. A 128, 9804–9818 (2024). (Rodney J. Bartlett Festschrift, special issue)
6	J. Kussmann, Y. Lemke, A. Weinbrenner, C. Ochsenfeld, "A Constraint-Based Orbital-Optimized Excited State Method (COOX)", J. Chem. Theory Comput. 20, 8461–8473 (2024).
5	Y. Lemke, C. Ochsenfeld, "Highly accurate σ- and τ-functionals for beyond-RPA methods with approximate exchange kernels", J. Chem. Phys. 159, 194104 (2023).
4	Y. Lemke, D. Graf, J. Kussmann, C. Ochsenfeld, "An assessment of orbital energy corrections for the direct random phase approximation and explicit σ-functionals", Mol. Phys. 121, e2098862 (2023); Special issue in honor of Professor Peter Gill.
3	Y. Lemke, J. Kussmann, C. Ochsenfeld, "Efficient Integral-Direct Methods for Self-Consistent Reduced Density Matrix Functional Theory Calculations on Central and Graphics Processing Units", J. Chem. Theory Comput. 18, 4229–4244 (2022).
2	A. Music, C. M. Nuber, Y. Lemke, P. Spieß, D. Didier, "Electro-alkynylation: Intramolecular Rearrangement of Trialkynylorganoborates for Chemoselective C(sp²)–C(sp) Bond Formation", Org. Lett. 23, 4179–4184 (2021).
1	M. Leroux, W.-Y. Huang, Y. Lemke, T. J. Koller, K. Karaghiosoff, "Pyrrole-Protected β-Aminoalkylzinc Reagents for the Enantioselective Synthesis of Amino-Derivatives", Chem. Eur. J. 26, 8951–8957 (2020).