Evaluation of relative electron ionization cross‐sections for some oxides and oxyacid salts

Abstract

The enthalpies of formation of gaseous cerium molybdates and tungstates were evaluated by measurements of the reaction enthalpies for several independent reactions. The best agreement was obtained with the data from the analysis of experimentally determined relative ionization cross-sections, and using ionization cross-sections of polyatomic molecules recommended by Drowart et al. The widely used additivity method, in spite of the additional corrections introduced, gives the worst convergence of the values under consideration.

Thermodynamic properties of gaseous BaSnO2 and Ba2O2 studied by Knudsen effusion mass spectrometry

“…The enthalpies of reactions 4–6 obtained by the 3 rd law (Equation ) and using the cross‐sections of reagents calculated by the additivity rule coincide within 3–4 kJ with the values obtained using the cross‐sections calculated according to the literature . Table S1 (supporting information) summarizes the data obtained using recommendations given in these citations …”

“…In particular, the analysis of the experimentally obtained cross‐sections revealed that σ(MO)/σ(M) = 0.65, and σ(M 2 O 2 )/σ (MO) = 1.25. For the cross‐sections of oxy‐acid salts we proposed using the sum of the cross‐sections of the oxides forming the salt, multiplied by 0.7 . The ionization cross‐sections ( σ i ) and the secondary electron multiplier gain factors (γ i ) for the gaseous species in the vapor over the BaO–SnO 2 system are listed in Table .…”

“…The indices “i” and “s” denote the sample and the standard, respectively. The values of the ionization cross‐section ratios σ Au /σ i where i is BaO, Ba 2 O 2 , SnO and BaSnO 2 were taken from the literature . The enthalpies of the reactions under study were calculated by the 2 nd and 3 rd law method (Equations and ).…”

“…The enthalpies of reactions 4-6 obtained by the 3 rd law (Equation (3)) and using the cross-sections of reagents calculated by the additivity rule coincide within 3-4 kJ with the values obtained using the cross-sections calculated according to the literature. 28,29 Table S1 (supporting information) summarizes the data obtained using recommendations given in these citations. 28,29 The enthalpies of reactions 4-6 determined for the middle of the temperature measurement range, equal to 1779 K, were found to be −359 ± 20, −362 ± 22 and −162 ± 16 kJ, respectively.…”

“…28,29 Table S1 (supporting information) summarizes the data obtained using recommendations given in these citations. 28,29 The enthalpies of reactions 4-6 determined for the middle of the temperature measurement range, equal to 1779 K, were found to be −359 ± 20, −362 ± 22 and −162 ± 16 kJ, respectively. The enthalpies of reactions obtained using Equations (2) and (3) Table S13 (supporting information) and taken from a reference handbook 25 gives us the value of −450 ± 42 kJ.…”