Mass spectrometric determination of the dissociation energies of the molecules CuLi, AgLi and AuLi

Abstract

Equilibria involving gaseous species CuLi, AgLi and AuLi have been investigated using a Knudsen effusion technique combined with mass spectrometric analysis of the vapour composition. The following dissociation energies were derived by the third law procedure from the measured ion intensities, free energy functions and auxiliary data :Di (CuLi) = 189.3 & 8.8 kJ mol-1 DG(AgLi) = 173.6k6.3 kJ mol-' Di(AuLi) = 280.8 2 6.5 kJ mol-I. 'The measured dissociation energies are considerably lower than those calculated from the Pauling model of the polar bond.There has been considerable interest recently in gaseous intermetallic compounds.1.2 The high stability of many of these compounds has been explained in terms of the Pauling model of the polar bond. No intermetallic gaseous compound of lithium has been observed so far, although one can expect relatively stable molecules between lithium and the elements of the IB group due to the large electronegativity difference between them.

Resonant two-photon ionization spectroscopy of LiCu

“…The plot demonstrates that the 21 420 cm Ϫ1 band of 7 Li 63 Cu is clearly the 6-0 band. Similar data using the isotope shifts between6 Li 63 Cu and 7 Li 63 Cu also strongly support this assignment.FIG. 3.…”

“…4 Apart from the work on LiCu and LiAg published earlier this year by Brock et al, which provides vibrationally resolved spectra of 12 band systems of LiCu lying within the range 29 500-36 200 cm Ϫ1 , 5 the only previous experimental work on LiCu of which we are aware is a Knudsen effusion mass spectrometric determination of the dissociation energy by Neubert and Zmbov in 1974. 6 They report D 0 (LiCu) ϭ1.96Ϯ0.09 eV based on an analysis of the reactions, CuLi͑g ͒→Cu͑ g ͒ϩLi͑ g ͒, ͑1.1͒…”

Evolution of geometrical structures, stabilities and electronic properties of neutral and anionic LinCuλ(n = 1–9,λ = 0, −1) clusters: compare with pure lithium clusters

“…The bond length and dissociation energies of LiCu dimer were calculated to be 2.26 Å and 2.01 eV, respectively, which are in good agreement with the values obtained in previous experimental investigation. [41,44,45] When the LiCu dimer attach an extra electron, the ground state of anion LiCu � will change to be 2 AE, and the bond length is elongated to 2.45 Å . Unfortunately, there are no available experimental values for comparison for anionic LiCu � dimer up to now, and our theoretical results need to be further verified by experiments.…”

“…The main objective of this research is to investigate the nature of interaction between lithium and copper atoms, meanwhile, to compare our extensive computational results with previous experimental findings. [41,[44][45][46] The various ground-state structures for Li n Cu � (n ¼ 1-9; � ¼ 0, �1) are also obtained, which can provide significant help for such cluster assembled materials.…”

Highly polar molecules consisting of a copper or silver atom interacting with an alkali-metal or alkaline-earth-metal atom

“…Additionally, Cu and Ag atoms have high electronegativity as compared with alkali-metal and alkaline-earth-metal atoms, promising strong bonding and large permanent electric dipole moments of the considered molecules. While the interactions of Cu and Ag atoms with noble gases have been the subject of several experimental [50][51][52][53] and theoretical [54][55][56] studies and the structure of the Cu 2 , CuAg and Ag 2 dimers have been actively explored [57][58][59][60][61][62][63][64][65][66][67][68], the interactions of Cu and Ag atoms with alkalimetal and alkaline-earth-metal metal atoms (and corresponding diatomic molecules) have been investigated in spectroscopic experiments occasionally [69][70][71][72][73][74] and in theoretical calculations rarely [49,[75][76][77][78].…”