Paper: Multireference Approaches for Excited States

We just published a comprehensive and quite voluminous review paper about “Multireference Approaches for Excited States of Molecules”  in Chemical Reviews. The paper covers the major methods used nowadays, such as CASSCF, multireference (MR) configuration interaction, MR perturbation theory, and MR coupled cluster. It discusses the application of semiempirical Hamiltonians as well as connections to DFT. The emerging algorithms DMRG and full-CI Quantum Monte Carlo are included as well. The theory of gradients as well as MR diagnostics and wavefunction analysis are discussed. The presented applications include a variety of cases starting from diatomics and going to complexes and dimers.

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Paper: Vibronic coupling constants

You can find our new paper “Interstate vibronic coupling constants between electronic excited states for complex molecules” that recently appeared in JCP. The purpose of this paper was the development of a method that allows to determine interstate vibronic coupling constants, which are a decisive ingredient for model Hamiltonians used in quantum dynamics. Our idea was to start with a method based on wavefunction overlaps that is commonly used for trajectory dynamics simulations and adapt it for the case of quantum dynamics.

Paper: Analysis of Transition Metal Complex Excited States

Doing computations on transition metal complexes can be very challenging. The problem is not only to find the correct computational method. But once the computation is finished, it is often difficult to even describe the results. The reason is that in the case of transition metal complexes there are many different possible types of state characters, a high density of states, and the orbitals are often not well resolved. Additional complications come into play due to spin-orbit coupling. For these reasons, we decided to  take a close look at how one could make the analysis of excited states in transition metal complexes easier.

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