The paper TheoDORE: A toolbox for a detailed and automated analysis of electronic excited state computations just appeared in the Journal of Chemical Physics in a special issue on Electronic Structure Software. Please, take a look if you are interested in speeding up the analysis of your excited-state computations. If you are already a user of TheoDORE, you can learn about the latest developments and obtain a compact overview of the underlying theory.
Splitting N2 is a challenging undertaking due to the strong triple bond holding the two nitrogen atoms together. Traditionally, this task is achieved via the Haber-Bosch process but recently interest has shifted to the possibilities of nitrogen splitting via homogeneous catalysis. Computations on the dinuclear transition metal complexes involved can be performed thanks to modern computational hardware and appropriate computer codes. However, the analysis of the excited states involved can become a significant challenge due to the large number of states and difficulties in assigning their character unambiguously. To tackle this problem, we have recently devised a strategy for a detailed analysis of the electronic wavefunctions of the states contributing to the reactive process. The associated paper, led by S. Rupp and V. Krewald from TU Darmstadt, just appeared in the European Journal of Inorganic Chemistry: Multi‐tier electronic structure analysis of Sita’s Mo and W complexes capable of thermal or photochemical N2 splitting.
An updated version of the tutorial for the TheoDORE wavefunction analysis program is ready, thanks to Patrick. The tutorial can be downloaded here:
For the newest version of the code go here:
In the tutorial, we explain the process of creating conditional electron densities for visualising electron correlation (ChemPhotoChem 2019, 3, 702). The figure below shows a comparison between the ionic and covalent singlet and triplet B3u states of naphthalene.
The tutorial also explains the creation of bar graphs for a compact representation of excited-state character (see Coord. Chem. Rev., 2018, 361, 74 and ChemRxiv.11395314). In the picture below, the excited states of an iridium complex are decomposed into metal-to-ligand charge transfer (MLCT), ligand-to-ligand charge transfer (LLCT), and ligand centred (LC) contributions. The lowest six states are all dominated by MLCT character but the presented analysis clearly shows that the first three have enhanced LC character compared to the latter three.
Two new preprints dealing with the analysis of excited-state electronic wavefunctions are available from ChemRxiv.
First, a quick summary of the TheoDORE package: TheoDORE: a Toolbox for a Detailed and Automated Analysis of Electronic Excited State Computations.
Second, a more extensive paper exploring how far we can use information from excited-state wavefunction analysis tools to understand excitation energies beyond the molecular orbital picture. The energy of a correlated electron-hole pair is derived using diagrammatic techniques and this information is further used for a graphical depiction in terms of different charge distributions and their electrostatic potentials. Doing so turned out not as easy as hoped for but was very exciting. Find more here: Toward an Understanding of Electronic Excitation Energies Beyond the Molecular Orbital Picture by P. Kimber and F. Plasser.
Tomorrow Felix will give a talk at the New Horizons in Materials Modelling 2020 taking place in York. Title: A toolbox for analysing structure-property relationships in functional molecules interacting with light.
You can download the slides here:
Tomorrow, Felix will give a talk at the Zernike Institute for Advanced Materials, Groningen. The talk is entitled: Understanding electronic excitation energies within and beyond the molecular orbital picture. It discusses how we can understand excited-state energies beyond simply looking at orbitals and their energies.
You can download the talk here:
On Thursday, 20/06, Felix will give a talk at the CECAM workshop on Theoretical and Computational Inorganic Photochemistry in Toulouse. This talk will discuss how excited states in transition metal complexes can be assigned completely automatically without ever looking at an orbital. It is shown how this method can be used for a high-throughput analysis of excited states as well as for benchmarking excited-state computations. Finally, a quick outlook will be given on how correlation effects can be visualised using a newly developed tool for computing conditional electron/hole densities.
You can download the slides here:
Version 2.0 of the TheoDORE wavefunction analysis package has been released, download below. The two main features of TheoDORE 2.0 are the computation of conditional electron densities and compatibility with python3.
Conditional electron densities can be used for the visualisation of excited-state electron correlation, see ChemPhotoChem (2019). Below, the application of this method to a PPV oligomer is shown. Here, the probe hole (red) is always fixed on the terminal phenyl ring and the different shapes for the conditional electron density (blue) for the first six excited states is observed. One can see that for the different states the electron is either repelled, attracted or unaffected by the hole.
On 5 September, Felix Plasser will give a talk entitled “Transition Metal Complex Excited States: Turning Numbers into Chemical Insight” at the Quantum-Bio-Inorganic Chemistry Conference IV in Bath. The talk will discuss the automatic assignment of excited-state character for transition metal complexes and present some recent results about using conditional electron densities for visualising excited-state correlation effects.
You can download the slides here:
On 29 August, Felix Plasser will give a talk entitled “Analysis of Excited-State Computations: Turning Numbers into Chemical Insight” at the 7th EuCheMS Chemistry Congress in Liverpool. The talk will present an automatic analysis of thousands of excited states in the case of interacting DNA nucleobases and introduce a method for analysing electron correlation effects in real space, exemplified in the case of a conjugated polymer.
You can download the slides here:
