Orbital energies and nuclear forces in DFT: Interpretation and validation

Abstract

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.

Helical versus linear Jahn–Teller distortions in allene and spiropentadiene radical cations

“…We will seek to outline this principle through a naive frontier MO picture; one where the change in the cation is considered on the basis that an electron is removed from the HOMO of the neutral species. 91 We explore the two types of JT distortion by examining substituted allenes and spiropentadienes, and assess the relation between their frontier MOs and the pseudo-JT distortion in their radical cations.…”

Helical versus linear Jahn-Teller distortions in allene and spiropentadiene radical cations

“…We will seek to outline this principle through a naive frontier MO picture; one where the change in the cation is considered on the basis that an electron is removed from the HOMO of the neutral species. 89 We explore the two types of JT distortion by examining substituted allenes and spiropentadienes, and assess the relation between their frontier MOs and the pseudo-JT distortion in their radical cations. relaxes into a higher energy structure with bond-length alternation (Figure 5).…”

Structural evolution and electronic properties of pure and semiconductor atom doped in clusters: Inn−, InnSi−, and InnGe− (n = 3–16)

“…isomer of neutral In 12 Si and In 12 Ge. The energy levels and spatial distributions of the occupied molecular orbitals of In In 12 Si, and In 12 Ge clusters are illustrated in Figures 4 and 5 [53][54][55][56][57][58]. These three clusters behave as superatoms [50][51][52].…”