Mass spectrometric investigation of the dissociation energy of the molecule AlAu and estimated bond energies of some diatomic intermetallic compounds with gold

Abstract

High-temperature Knudsen-cell mass spectrometry has been used to measure the gaseous equilibria over an aluminum-gold or aluminum-silver-gold alloy in a tantalum cell. The enthalpies for the reactions (1) AlAu(g) = Al(g) + Au(g), and (2) AlAu(g) + Au(g) = Au2(g) + Al(g) were measured. The following dissociation energy D°0, heat of sublimation Δ H°s,298, and heat of formation Δ H°f,298 were derived from these reaction enthalpies for gaseous AlAu: 77.0 ± 1.5, 98.4 ± 2.5, and 88.9 ± 2.0 kcal mole−1, respectively. The dissociation energy of AlAu(g) has been interpreted in terms of the Pauling model of a polar bond. This model has been used to calculate dissociation energies of selected intermetallic compounds between transition metals, Group III metals, and Group IV metals with gold, which are compared with available literature data.

Density functional study on size-dependent structures, stabilities, electronic and magnetic properties of Au n M (M = Al and Si, n = 1–9) clusters: comparison with pure gold clusters

“…Its equilibrium bond length is 2.39 Å, which overestimates the measured value 2.34 Å. However, the calculated vibrational frequency 318 cm −1 and dissociation energy 3.48 eV fall close to experimental results of 330 cm −1 and 3.37 ± 0.13 eV [44,45]. For AuSi, its theoretical results of bond length 2.28 Å and dissociation energy 3.17 eV are in good agreement with available experimental data 2.26 Å [46] and 3.16 eV [47].…”

Structures of Nanoalloy Clusters AunAln(n= 1–10) and the Growth Patterns to the Bulk Phase

“…The diatomic AuAl has a C ∞ v symmetry with the calculated vibrational frequencies of 332.6 cm –1 , which is in excellent agreement with the experimental results of 333 cm –1 . The ground-state geometry of the Al 2 Au 2 cluster has a tetrahedral structure with the C 2 v symmetry, identical to the experimentally identified structure by high-resolution PES .…”

“…Colloquially known as “superatoms”, some Al clusters have been found to behave analogously to the halogen, alkaline earth, and other multivalent species . Alloyed Au x Al y clusters have been actively explored, and a rich spectrum of structures was discovered, ranging from Au-rich Au 5 Al to Al-rich AuAl 12 , through various techniques including photoelectron spectroscopy (PES), high-resolution photoelectron imaging, and first-principles calculations. − In this group, the clusters with (nearly) equal compositions, i.e., x ≈ y , were relatively less studied until the recent discovery of Al 2 Au 2 , followed by a series of new alloyed clusters Au x Al y – ( x + y = 7, 8; x = 1–3; y = 4–7) . Motivated by these new findings, in this paper, we theoretically investigated the Au n Al n clusters, where the Al and Au have equal compositions, in the range n = 2–10.…”

The structural and electronic properties of tubular gold clusters with a spinal support

“…After the geometry optimizations were performed, it was found that the dopant atoms had not distorted the tube like structure of Au 42 and still formed a linear chain at the centre of the tube. In the Au doped Au 48 cluster, it was found that similar to the case of Au 3 Au 24 , one of the gold atoms lying at the central axis had moved to form a rhombus at one end of the tube, while the rest 1.95 1.67 57,59 of the Au atoms formed a chain. Interestingly, as Fig.…”