10.26434/chemrxiv.12517457.v1
RubĂ©n Laplaza
Julia Contreras-Garcia
Patrick Chaquin
Carlos Cardenas
Paul W. Ayers
Orbital Energies and Nuclear Forces in DFT: Interpretation and Validation
2020
ChemRxiv
Molecular Orbital Analysis
Molecular Orbitals
Density Functional Theory
Koopmans Theorem
Nuclear Forces
2020-06-24 13:06:09
article
https://chemrxiv.org/articles/preprint/Orbital_Energies_and_Nuclear_Forces_in_DFT_Interpretation_and_Validation/12517457
The bonding and antibonding character of individual Molecular Orbitals has been previously shown to be related to their orbital energy derivatives with respect to nuclear coordinates, known as Dynamical Orbital Forces. Albeit usually derived from Koopmans' theorem, in this work we show a more general derivation from conceptual DFT, which justifies application in a broader context. The consistency of the approach is validated numerically for valence orbitals in Kohn-Sham DFT. Then, we illustrate its usefulness by showcasing applications in aromatic and antiaromatic systems and in excited state chemistry. Overall, Dynamical Orbital Forces can be used to interpret the results of routine ab initio calculations, be it wavefunction or density based, in terms of forces and occupations.