Decomposition of Bis(acetylacetonate)zinc(II) by Slow Electrons

Abstract

The production of zinc-containing nanostructures has a large variety of applications. Using electron beam techniques to degrade organometallic molecules for that purpose is perhaps one of the most versatile methods. In this work, we investigate the scattering of low-energy (<12 eV) electrons with bis(acetylacetonate)zinc(II) molecules. We show that core excited and high-lying shape resonances are mainly responsible for the production of the precursor anions as well as the ligand negative fragments, which are observed exclusively at electron energies of >3 eV. The mechanisms for electron capture and then molecular dissociation are discussed in terms of density functional theory studies.

Fragmentation of metal(II) bis(acetylacetonate) complexes induced by slow electrons

“…We performed a series of collision experiments of low-energy electrons with metal bis(acetylacetonate)s, ML 2 , where M and L represent a metal (Mn, Co, Ni, Cu, and Zn) and the acetylacetonate ligand, respectively. Previous reports were only dedicated to the mechanism and the energetics for the production of the two predominant species, that is, the parent [ML 2 ] − anion and the ligand [L] − anion [15][16][17][18][19]. In addition to these two species, the interaction of slow electrons with the metal chelates also produces a rich variety of fragment anions, which are reported and discussed in the present report.…”

“…4 eV for most organic molecules. However, for molecules that contain metal atoms, this energy can be as low as 1.3–1.4 eV [ 17 ]. The formation of the [ML 2 ] − anion via the core-excited resonance occurs in NiL 2 and ZnL 2 at around 5 and 8 eV, respectively ( Figure 1 ).…”

“…Such a process usually arises typically at electron energies below 4 eV. The molecular orbitals into which the excess electron may be trapped are reported in [15][16][17][18][19] for the investigated organometallic systems. Alternatively, the electron can also be attached to an electronically excited state resulting in coreexcited or Feshbach resonances [21].…”

“…We performed electron collision experiments with several metal acetylacetonate compounds, ML 2 , in a crossed-beam arrangement. According to the description given in [ 16 – 17 29 ], this arrangement consists of an electron source, an oven, and a quadrupole mass analyzer (QMA). The components are housed in a UHV chamber at a base pressure of around 2 × 10 −8 mbar.…”

Multi-Basis-Set (TD-)DFT Methods for Predicting Electron Attachment Energies

“…It is noteworthy that the scaling factor strongly depends on the level of theory (e.g., choices of the correlation method, the density functional, and the basis set) and possibly on the nature of molecules and excitations investigated. Consequently, several fits can be found in the literature. − …”