Vibrational spectra and structures of bare and Xe-tagged cationic SinOm+ clusters

Savoca, Marco; Langer, Judith; Harding, Dan J.; Palagin, Dennis; Reuter, Karsten; Dopfer, Otto; Fielicke, André

doi:10.1063/1.4894406

Cited by 17 publications

(35 citation statements)

References 69 publications

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“…calculations, whereby the latter was used to assign isomer structures to observed IR absorption spectra. 7,8 Here the tendency for Si+Si bond formation was found to start at (SiO) 4 + , which is also confirmed in another purely theoretical study. bonding.…”

supporting

confidence: 72%

Under what conditions does (SiO)_N nucleation occur? A bottom-up kinetic modelling evaluation

Bromley

Martı́n

Plane

2016

Phys. Chem. Chem. Phys.

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* Corresponding authors: s.bromley@ub.edu, J.M.C.Plane@leeds.ac.uk Silicon monoxide (SiO) is a structurally complex compound exhibiting differentiated oxide+ rich and silicon+rich nano+phases at length scales covering nanoclusters to the bulk. Although nano+sized and nano+segregated SiO has great technological potential (e.g. nano+silicon for optical applications) and is of enormous astronomical interest (e.g. formation of silicate cosmic dust) an accurate general description of SiO nucleation is lacking. Avoiding the deficiencies of a bulk+averaged approach typified by classical nucleation theory (CNT) we employ a bottom+up kinetic model which fully takes into account the atomistic details involved in segregation. Specifically, we derive a new low energy benchmark set of segregated (SiO) N cluster ground state candidates for N ≤ 20 and use the accurately calculated properties of these isomers to calculate SiO nucleation rates. We thus provide a state+of+the art evaluation of the range of pressure and temperature conditions for which formation of SiO will or will not proceed. Our results, which match with available experiment, reveal significant deficiencies with CNT approaches. We employ our model to shed light on

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supporting

confidence: 72%

Under what conditions does (SiO)_N nucleation occur? A bottom-up kinetic modelling evaluation

Bromley

Martı́n

Plane

2016

Phys. Chem. Chem. Phys.

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“…If the IR radiation resonantly couples to a vibrational mode, multiple photons can be absorbed, which heats up the cluster and leads to its dissociation (for example, evaporation of Ng atoms). The mass signal depletion monitored as a function of the FELIX wavelength leads to IR spectra, which are shown on a cross‐section scale 33…”

Section: Partial Charges From Population Analyses Employing the Löwdimentioning

confidence: 99%

“…Them ass signal depletion monitored as af unction of the FELIX wavelength leads to IR spectra, which are shown on across-section scale. [33] Thet rimer isomers including Ar atoms are locally optimized using NWChem v6.3, [34] employing the def2-TZVPP basis set and the corresponding scalar relativistic small-core effective core potential (def2-ECP). [35] Thel ongrange corrected xc functional LC-wPBEh [36] is used, which has been shown to reliably reproduce optical spectra.…”

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confidence: 99%

The Nature of Bonding between Argon and Mixed Gold–Silver Trimers

et al. 2015

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The controversial nature of chemical bonding between noble gases and noble metals is addressed. Experimental evidence of exceptionally strong Au-Ar bonds in Ar complexes of mixed Au-Ag trimers is presented. IR spectra reveal an enormous influence of the attached Ar atoms on vibrational modes, particularly in Au-rich trimers, where Ar atoms are heavily involved owing to a relativistically enhanced covalency. In Ag-rich trimers, vibrational transitions of the metal framework predominate, indicating a pure electrostatic character of the Ag-Ar bonds. The experimental findings are analyzed by means of DFT calculations, which show how the relativistic differences between Au and Ag are manifested in stronger Au-Ar binding energies. Because of the ability to vary composition and charge distribution, the trimers serve as ideal model systems to study the chemical nature of the bonding of noble gases to closed-shell systems containing gold.

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“…Albeit silicon monoxide and magnesia are less refractory and hence less likely to trigger dust nucleation in AGB stars, they represent basic building blocks of silicates and are included in our study. Previous studies have addressed the four nucleation candidates MgO, SiO, Al 2 O 3 , and TiO 2 , and described the properties of the related neutral clusters in astrophysical environments theoretically [19][20][21], and experimentally [22][23][24]. We note, however, that it is probable that chemically-heterogeneous compounds involving several clustering species could play a role in the rich gas-phase mixtures of AGB circumstellar envelopes.…”

Section: Introductionmentioning

confidence: 95%

The Ionization Energies of Dust-Forming Metal Oxide Clusters

et al. 2021

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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 investigated the vertical and adiabatic ionization energies of four different metal-oxide clusters by means of density functional theory. They included 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 showed relatively little variation in their ionization energies with respect to the cluster size n: 7.1–8.2 eV for (MgO)n, from 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.

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Vibrational spectra and structures of bare and Xe-tagged cationic SinOm+ clusters

Cited by 17 publications

References 69 publications

Under what conditions does (SiO)_N nucleation occur? A bottom-up kinetic modelling evaluation

Under what conditions does (SiO)_N nucleation occur? A bottom-up kinetic modelling evaluation

The Nature of Bonding between Argon and Mixed Gold–Silver Trimers

The Ionization Energies of Dust-Forming Metal Oxide Clusters

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Vibrational spectra and structures of bare and Xe-tagged cationic SinOm+ clusters

Cited by 17 publications

References 69 publications

Under what conditions does (SiO)N nucleation occur? A bottom-up kinetic modelling evaluation

Under what conditions does (SiO)N nucleation occur? A bottom-up kinetic modelling evaluation

The Nature of Bonding between Argon and Mixed Gold–Silver Trimers

The Ionization Energies of Dust-Forming Metal Oxide Clusters

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Under what conditions does (SiO)_N nucleation occur? A bottom-up kinetic modelling evaluation

Under what conditions does (SiO)_N nucleation occur? A bottom-up kinetic modelling evaluation