The ionization energies of dust-forming metal oxide clusters

David Gobrecht, Jan Philip Sindel, Helena Lecoq Molinos, Leen Decin

Research output: Contribution to journalArticlepeer-review


Stellar dust grains are predominantly composed of mineralic, anorganic material forming in the circumstellar envelopes of oxygen-rich AGB stars. However, the initial stage of the dust synthesis, or its nucleation, is not well understood. In particular, the chemical nature of the nucleating species, represented by molecular clusters, is uncertain. We investigate the vertical and adiabatic ionization energies of four different metal-oxide clusters by means of density functional theory. They include clusters of magnesia (MgO)n, silicon monoxide (SiO)n, alumina (Al2O3)n, and titania (TiO2)n with stoichiometric sizes of n=1−8. The magnesia, alumina and titania clusters show relatively little variation in their ionization energies with respect to the cluster size n, ranging from 7.1−8.2 eV for (MgO)n, 8.9−10.0 eV for (Al2O3)n, and 9.3−10.5 eV for (TiO2)n. In contrast, the (SiO)n ionization energies decrease with size n, starting from 11.5 eV for n=1, and decreasing to 6.6 eV for n=8. Therefore, we set constraints on the stability limit for neutral metal-oxide clusters to persist ionization through radiation or high temperatures and for the nucleation to proceed via neutral-neutral reactions
Original languageEnglish
Article number243
Number of pages11
Issue number7
Publication statusPublished - 14 Jul 2021


  • Metal oxide
  • Ionization
  • Clusters
  • Condensation
  • Cations
  • Dust
  • Silicates
  • Circumstellar
  • Minerals
  • Bottom-up


Dive into the research topics of 'The ionization energies of dust-forming metal oxide clusters'. Together they form a unique fingerprint.

Cite this