A theoretical study of the gas-phase chemi-ionization reaction between uranium and oxygen atoms

Abstract

The U + O chemi-ionization reaction has been investigated by quantum chemical methods. Potential-energy curves have been calculated for several electronic states of UO and UO + .Comparison with the available spectroscopic and thermodynamic values for these species is reported and a mechanism for the chemi-ionization reaction U + O → UO + + e − is proposed. The U + O and Sm+ O chemi-ionization reactions are the first two metal-plus-oxidant chemi-ionization reactions to be studied theoretically in this way.

Probing the electronic structure of UO+ with high-resolution photoelectron spectroscopy

“…16 There have been several theoretical calculations of the IE for UO, the most recent being the CASSCF-configuration interaction calculation of Tyagi, 6 where the spin-orbit operator was included from the outset ͑IE= 5.59 eV͒ and the CASSCF-SOC calculations of Paulovič et al, 2 where spin-free calculations preceded evaluation of the terms associated with the spin-orbit operator ͑IE= 6.05 eV͒. 16 There have been several theoretical calculations of the IE for UO, the most recent being the CASSCF-configuration interaction calculation of Tyagi, 6 where the spin-orbit operator was included from the outset ͑IE= 5.59 eV͒ and the CASSCF-SOC calculations of Paulovič et al, 2 where spin-free calculations preceded evaluation of the terms associated with the spin-orbit operator ͑IE= 6.05 eV͒.…”

“…2,5,6 In order to make comparisons with these results we make the assumption that the experimental value for the equilibrium bond length can be approximated from the expression 2,5,6 In order to make comparisons with these results we make the assumption that the experimental value for the equilibrium bond length can be approximated from the expression …”

Ionization Energies for the Actinide Mono- and Dioxides Series, from Th to Cm: Theory versus Experiment

“…Upon ionization the electron is removed from a 7s shell, and as a consequence the SO effect on IE1 is only about 0.01 eV. This molecule was studied at the CASPT2 level of theory by Paulovic et al, 57 who reported a IE1 value of 6.05 eV, in agreement with the experimental value measured by Goncharov et al, 58 6.0313 ( 0.0006 eV. Paulovic et al 57 did not report a value for IE2, which we now report in this study.…”

Theoretical Study of the Gas-Phase Chemiionization Reactions La + O and La + O2

“…Reaction 5 followed by reaction 6 has already been demonstrated as the source of the chemielectron band observed in a study of the U + O 2 chemiionization reaction. 8,9 In the experimental study of lanthanum with the oxidants O 2 (X 3 Σ g ), O 2 (a 1 ∆ g ) and O( 3 P), 6,7 the La + O 2 (X 3 Σ g ) reaction gave a chemielectron band with a most probable kinetic energy (MPKE) (band maximum) of 1.03 ( 0.20 eV and a high kinetic energy offset (HKEO) of 1.5 ( 0.1 eV. For the La + O 2 (a 1 ∆ g ) reaction, these values were 2.41 ( 0.06 and 3.3 ( 0.1 eV, whereas for the La + O( 3 P) reaction they were 0.67 ( 0.06 and 1.8 ( 0.1 eV.…”