Mass Spectrometric Study of Gaseous Oxides of Rhodium and Palladium

Thermodynamic properties of RhO2

“…Data for solid Rh 2 O 3 is from reference [6], for solid RhO 2 from this study, for RhO gas from reference [17] and for RhO 2 from reference [11]. It is seen that the gas species RhO is very unstable and can be detected by mass-spectrometry only at very high temperatures [10]. Species RhO 2 is relatively more stable.…”

“…Norman et al [10] have detected both RhO and RhO 2 species in the gas phase using Knudsen cell mass-spectrometry, with constant flow of oxygen into the Knudsen cell at partial pressures varying from 10 −5 < P O 2 /P o < 10 −3 . These experiments were conducted in the temperature range from 1903 to 2173 K. Alcock and Hooper [11] studied the volatility of Rh as a function of oxygen partial pressure from 1273 to 1773 K. They show that RhO 2 is the predominant gas species.…”

Kinetic energy dependence of the reactions of Ru+, Rh+, Pd+, and Ag+ with O2

“…In most cases, the best values for the neutral heats of formation can be taken from the critical evaluation of Pedley and Marshall ͑PM͒, 12 Table I. For AgO, this is taken from work of Smoes et al 13 For RuO and RhO, these values are taken from work of Norman et al 14,15 These authors also have the only experimental determination of ⌬ f H 298 ‫ؠ‬ ͑PdO͒, 3.63Ϯ0.13 eV. 16 PM discounted this value because they believed that it was too high, and instead estimated a value of 2.55Ϯ0.87 eV.…”

“…Comparison with theoretical calculations of Siegbahn, 17 however, suggests that the experimental value is likely to be fairly accurate and it has been adopted by Lias et al 11 The only available IE͑MO͒ values are electron impact values that come from the high temperature mass spectrometry studies. 14,15 Because these values were measured simply to verify that detection of the MO ϩ signal did not come from dissociation of a larger molecule, they are not particularly reliable and have uncited uncertainties that probably range from 0.5 to 1.0 eV.…”

Theoretical study on the gas‐phase reaction mechanism between palladium monoxide and methane

“…[26,71,[84][85][86][87][88] It should be noted that the same method B3LYP and comparatively small basis set were adopted in the PdO þ CH 4 system by Hwang et al [26] That is, the RECP of Dolg and coworkers [89] and the associated triple-f basis set with addition of the f polarization functions were used for Pd, and Dunning's correlation consistent basis set cc-pVTZ [90] was used for H, C, and O, while excluding f functions on O and C and d function on H. [26] Furthermore, the same method CCSD(T) and basis set AVTZ were explored in the Pd þ CH 4 system by Quintal et al [52] It is proposed that CCSD(T) is the minimum acceptable level of theory, and the AVTZ basis set is somewhat extensive in terms of both diffuse and angular correlation coverage. [52] Therefore, the present theoretical method of CCSD(T)/ AVTZ//B3LYP/6-311þG(2d, 2p), SDD should be appropriate and reliable for the PdO þ CH 4 system.…”