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The chemistry occurring in astrophysical environments is primarily controlled by the carbon-overoxygen (C/O) ratio. This is a consequence of the high carbon monoxide (CO) bond energy of 11.2 eV making CO the most stable diatomic molecule known (Luo, 2007). This classical dichotomy is challenged since non-equilibrium processes such as photo-chemistry and pulsation-induced shocks can break the strong CO bond and lead to the formation of unexpected molecules (Agúndez et al., 2010; Gobrecht et al., 2016). Of particular astronomical interest are refractory molecules and molecular clusters that represent the precursors of circumstellar dust. One of the main dust species in carbon-dominated regimes is silicon carbide (SiC). A broad spectral feature around 11.3 micron is commonly observed in Carbon-rich evolved starts and attributed to the presence of SiC dust grains (Friedemann, 1968; Hackwell, 1972; Treffers and Cohen, 1974). SiC stardust was extracted from pristine meteorites (Bernatowicz et al., 1987; Amari et al., 1994; Hoppe et al., 1996; Zinner et al., 2007; Liu et al., 2014). Recent studies have shown that the vast majority of presolar SiC grains found in pristine meteoritic stardust originate from low-mass Asymptotic Giant Branch (AGB) stars (Cristallo et al., 2020). But also molecular gas-phase species like SiC, Si2C, SiC2 were detected in the circumstellar envelopes of carbon-rich evolved stars (Thaddeus et al., 1984; Cernicharo et al., 1989; McCarthy et al., 2015; Massalkhi et al., 2018). The evidence for both, gas-phase siliconcarbon molecules and solid SiC dust suggests that their intermediaries, i.e., SiC molecular clusters, also exist in carbon-rich astronomical environments and partake in the nucleation and SiC dust formation process. Therefore, SiC molecular clusters are the objects of our interest. This study represents a continuation of a prior work (Gobrecht et al., 2017) and addresses the (single) ionization energies of the previously investigated neutral (SiC)n, n= 1–12, clusters. This paper is organized as follows. In section 2, we present the methods used to derive the vertical and adiabatic ionization energies. Section 3 shows the results for these energies as well as the adiabatically optimized cation geometries and in section 4 our summary and conclusion is given.

The Vertical and Adiabatic Ionization Energies of Silicon Carbide Clusters, (SiC)n, With n = 1–12