G. Balducci

Mass Spectrometric Study of the Vaporization of Cuprous Chloride and the Dissociation Energy of Cu3Cl3, Cu4Cl4, and Cu5Cl5

The vapor phase in equilibrium with cuprous chloride has been studied using the Knudsen effusion‐mass spectrometric technique. The polymeric species Cu3Cl3, Cu4Cl4, and Cu5Cl5 were observed, the first two in comparable amounts. Partial pressures and heats of vaporization for each species were measured: 3u2009CuCl(s)→Cu3Cl3(g),u2009u2009u2009Δ H640o=33.7± 0.8u2009kcal/mole, 4u2009CuCl(s)→Cu4Cl4(g),u2009u2009u2009Δ H650o=34.6± 0.7u2009kcal/mole, 5u2009CuCl(s)→Cu5Cl5(g),u2009u2009u2009Δ H665o=41± 1u2009kcal/mole. The atomization energies for these molecules calculated on the basis of the Rittner ionic model are compared with the experimental values.

Dissociation Energy of CuCl and Cu2Cl2 Gaseous Molecules

Using the mass spectrometric and double oven technique, the molecules CuCl(g) and Cu2Cl2(g) have been observed in the superheated vapors of cuprous chloride. From the study of the various gaseous equilibria, the atomization energies of CuCl(g) and Cu2Cl2(g), D0o(CuCl)=90.6± 1.1 and D0o(Cu2Cl2=225.8± 1.1u2009kcal/mole, were derived. Polymerization energies of CuCl to dimer, trimer and tetramer, and the energy of formation of Cu2Cl2(g) from trimer and tetramer were also determined.

Mass spectrometric study of the thermochemistry of gaseous EuTiO3 and TiO2

The gaseous molecule EuTiO3 has been investigated in a high temperature mass spectrometric study of vapors over the europium–titanium–oxygen system. From the enthalpy of reaction: EuTiO3(g)=EuO(g)+TiO2(g) and proper ancillary data, the atomization energy of this molecule has been determined. In addition, from the study of the gaseous exchange reaction: TiO2(g)+Eu(g)=TiO(g)+EuO(g) the dissociation energy of TiO2(g) has been derived and compared with previous results. The dissociation energies proposed are: D○0,at(EuTiO3) =2278±28 kJu2009mol−1 and D○0,at(TiO2) =1260±12 kJu2009mol−1.

Dissociation energies of the intermetallic molecules CuIn, AgIn, and AuIn

The gaseous diatomic intermetallic molecules of the IA‐IIIB groups, elements CuIn, AgIn, and AuIn, were investigated in a Knudsen cell‐mass spectrometric study of the vapors over the respective alloys. From a number of all‐gas equilibria their dissociation energies have been derived: Do0(CuIn) =183.7±7.9, Do0(AgIn) =162.8±4.9, Do0(AuIn) =282.3±5.7 kJ/mol. These values were compared to the values calculated from empirical models of bond. Of particular interest is the strikingly high dissociation energy of AuIn which was interpreted in terms of relativistic effects rather than due to multiple bond. The implications in the indium electronegativity value and the mode of formation of AuIn(g) are also discussed.

Ru K-edge absorption study on the La1-xCexRu2 system

We have measured high-resolution Ru K-edge x-ray absorption spectra for the intermetallic La1-xCexRu2 system. Multiple-scattering calculations are made to explore the origins of different features observed in the experimental x-ray absorption near-edge structure (XANES) and their variation with Ce doping. The experiments and theoretical analysis demonstrate that the Ce doping in La1-xCexRu2 has a direct influence on the states at the Fermi level and hence the hybridization between the f and d states induced by doping.

Dissociation Energies of the Ga2, In2, and GaIn Molecules

The group III metal dimers Ga2 and In2 and the newly identified intermetallic molecule GaIn were investigated in a Knudsen cell-mass spectrometric study of the vapors over gallium–indium alloys. From the all-gas equilibria analyzed by the second-law and third-law methods the following dissociation energies were derived; D00 (Ga2)=110.8±4.9u2009kJu2009mol−1, D00 (In2)=74.4±5.7u2009kJu2009mol−1, D00 (GaIn)=90.7±3.7u2009kJu2009mol−1. The value here measured for the dissociation energy of In2 is discussed and compared with a previous experimental determination and with the results of more recent theoretical investigations.

Experimental and computational study of the new gaseous molecules OMnF and OMnF2

The new gaseous species OMnF and OMnF2 were identified and studied by high-temperature Knudsen Cell Mass Spectrometry. Their thermochemical atomization energies were derived through the study of several all-gas equilibria in the temperature range 1735–1913 K. FTIR matrix isolation experiments together with ab initio and density functional calculations were performed to determine the molecular parameters, bond distances, and vibrational frequencies of OMnF(g) and OMnF2(g). The results allowed us to evaluate a set of thermal functions for the new species that were used in the evaluation of the equilibrium data. The proposed atomization energies and enthalpies of formation are ΔaH0∘(OMnF,g)=(903±5)u2009kJu200amol−1, ΔfH298.15∘(OMnF,g)=(−297±5)kJu200amol−1, and ΔaH0∘(OMnF2,g)=(1470±70)u2009kJu200amol−1, ΔfH298.15∘(OMnF2,g)=(−789±70)kJu200amol−1.

Identification and stability determinations for the gaseous titanium oxide molecules Ti2O3 and Ti2O4

The gaseous titanium oxides molecules Ti2O3 and Ti2O4 were observed for the first time by high temperature mass spectrometry in the vapors over a cobalt–titanium–oxygen system. From the study of three all‐gas reaction equilibria, the stabilities of these molecules have been derived: D○0,at(Ti2O3) =2312±56 kJu2009mol−1 and D○0,at (Ti2O4)=3017±47 kJu2009mol−1. The appearance potentials were measured to be 8.3±0.5 and 10.5±0.5 eV for Ti2O+3 and Ti2O+4, respectively.

Mass spectrometric determination of the dissociation energy of the AuMg diatomic molecule

The dissociation energy of the intermetallic molecule AuMg was for the first time determined by the Knudsen-effusion mass spectrometry technique. Partial pressures of Au(g), Mg(g), AuMg(g) and Au2(g) species produced under equilibrium vaporization of an appropriate alloy were monitored in the temperature range 1870–2333 K. The collected data were analyzed by the second- and third-law methods for the gaseous equilibria AuMg(g) ¼ Au(g) + Mg(g) and AuMg(g) + Au(g) ¼ Au2(g) + Mg(g). The selected value for the dissociation energy of AuMg at 0 K is D � (AuMg) ¼

Identification and stability of U2O2, U2O3, and U2O4 gaseous oxides molecules

The U2O3(g) and U2O4(g) species have been for the first time identified by Knudsen cell‐mass spectrometry and their heats of formation and atomization energies have been tentatively derived. A redetermination of these quantities for the already known UO3(g) and U2O2(g) molecules has been also attempted.