• Development and application of wave-function-based quantum-chemical methods using Slater-type two-electron basis functions in the framework of the random-phase approximation (RPA) for the computation of electron-correlation energies in density-functional theory [1, 2], and in the framework of symmetry adapted perturbation theory (SAPT) for the computation and analysis of weakly bonded complexes [3].
  • Computation of electronic absorption and emission spectra of oligonuclear transition-metal- and lanthanoid complexes [4, 5, 6].
  • Development and application of two-component coupled-cluster methods for ground- and excited states (by response theory) in vacuum as well as in solution, accounting for spin-orbit effects [7, 8].
  • Computation of benchmark data for binding energies of weakly bonded complexes, for example bonded by hydrogen bonds or
    π-π interactions [9, 10].


Selected Publications


  1. A.-S. Hehn and W. Klopper, Communication: Explicitly-correlated second-order correction to the correlation energy in the random-phase approximationJ. Chem. Phys. 138, 181104 (2013).
  2. A.-S. Hehn, D. P. Tew, and W. Klopper,  Explicitly correlated ring-coupled-cluster-doubles theory,  J. Chem. Phys. 142, 194106 (2015).
  3. J. A. Frey, C. Holzer, W. Klopper, and S. Leutwyler, Experimental and theoretical determination of dissociation energies of dispersion-dominated aromatic molecular complexes, Chem. Rev. 116, 5614-5641 (2016).
  4. J. Chmela, M. E. Harding, D. Matioszek, C. E. Anson, F. Breher, and W. Klopper, Differential many-body cooperativity in electronic spectra of oligonuclear transition-metal complexes, ChemPhysChem 17, 37-45 (2016).
  5. J.-F.  Greisch, J. Chmela, M. E. Harding, W. Klopper, M. M. Kappes, and D. Schooss, Gas-phase photoluminescence characterization of stoichiometrically pure nonnuclear lanthanoid hydroxo complexes comprising europium or gadolinium, Inorg. Chem. 55, 3316-3323 (2016).
  6. M. Zimmer, F. Rupp, P. Singer, F. Walz, F. Breher, W. Klopper, R. Diller, and M. Gerhards, Time-resolved IR spectroscopy of a trinuclear palladium complex in solution, Phys. Chem. Chem. Phys. 17, 14138-14144 (2015).
  7. K. Krause and W. Klopper, Communication: A simplified coupled-cluster Lagrangian for polarizable embedding, J. Chem. Phys. 144, 041101 (2016).
  8. K. Krause and W. Klopper, Description of spin–orbit coupling in excited states with two-component methods based on approximate coupled-cluster theory, J. Chem. Phys. 142, 104109 (2015).
  9. S. Ahnen, A.-S. Hehn, K. D. Vogiatzis, M. A. Trachsel, S. Leutwyler, and W. Klopper, Accurate computations of the structures and binding energies of the imidazole...benzene and pyrrole...benzene complexes, Chem. Phys. 441, 17-22 (2014).
  10. M. E. Harding and W. Klopper, Benchmarking the lithium-thiophene complex, ChemPhysChem 14, 708-715 (2013).