Yannick Lemke

	Yannick Lemke, M.Sc., PhD student
	Room:	BZ5.014
	Phone:	+49 89 2180-72409
	E-Mail:	yannick.lemkecup.uni-muenchen.de
	ORCID:	0000-0002-0930-5287

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 facilitates 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

10	Y. Lemke, J. Kussmann, C. Ochsenfeld, "A detailed comparison of ΔSCF methods with the constraint-based orbital-optimized excited state method", Commun. Chem. 9, 162 (2026).
9	Y. Lemke, J. Kussmann, C. Ochsenfeld, "Nonorthogonal Configuration Interaction of Constraint-Based Orbital-Optimized Excited States: A Versatile Method for Theoretical Photochemistry", J. Chem. Theory Comput. 21, 10193–10211 (2025).
8	J. Liebert, Y. Lemke, M. Altunbulak, T. Maciazek, C. Ochsenfeld, C. Schilling, "Toolbox of spin-adapted generalized Pauli constraints", Phys. Rev. Res. 7, 023247 (2025).
7	Y. Lemke, J. Kussmann, C. Ochsenfeld, "An embedding scheme for constraint-based orbital-optimized excitations in molecular and bulk environments", Phys. Chem. Chem. Phys. 27, 12161–12170 (2025). (Christel Marian Festschrift, special issue)
6	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)
5	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)
4	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).
3	Y. Lemke, C. Ochsenfeld, "Highly accurate σ- and τ-functionals for beyond-RPA methods with approximate exchange kernels", J. Chem. Phys. 159, 194104 (2023).
2	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). (Peter Gill Festschrift, special issue)
1	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).

Further Publications

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, P. Knochel, "Pyrrole-Protected β-Aminoalkylzinc Reagents for the Enantioselective Synthesis of Amino-Derivatives", Chem. Eur. J. 26, 8951–8957 (2020).