Methane Oxidation to Methanol without CO2 Emission: Catalysis by Atomic Negative Ions

The catalytic activities of the atomic Y-, Ru-, At-, In-, Pd-, Ag-, Pt-, and Os- ions have been investigated theoretically using the atomic Au- ion as the benchmark for the selective partial oxidation of methane to methanol without CO2 emission. Dispersion-corrected density-functional theory has been used for the investigation. From the energy barrier calculations and the thermodynamics of the reactions, we conclude that the catalytic effect of the atomic Ag-, At-, Ru-, and Os- ions is higher than that of the atomic Au- ion catalysis of CH4 conversion to methanol. By controlling the temperature around 290K (Os-), 300K (Ag-), 310K (At-), 320K (Ru-) and 325K (Au-) methane can be completely oxidized to methanol without the emission of CO2. We conclude by recommending the investigation of the catalytic activities of combinations of the above negative ions for significant enhancement of the selective partial oxidation of methane to methanol.

Intersection of low-energy electron-atom scattering and photodetachment of negative ions

We propose to use the near-threshold electron scattering data for atoms to guide the reliable experimental determination of their electron affinities (EAs), extracted using the Wigner Threshold Law, from laser photodetachment threshold spectroscopy measurements. Data from the near-threshold electron elastic scattering from W, Te, Rh, Sb and Sn atoms calculated using our complex angular momentum method, wherein is embedded the electron-electron correlations and core polarization interaction, are used as illustrations. We conclude with a remark on the relativistic effects on the EA calculation for the heavy At atom.

Comment on Experimental Studies of Os^-: Observation of a Bound-Bound Electric Dipole Transition in an Atomic Negative Ion

Bilodeau and Haugan [1], using Infrared laser photodetachment spectroscopy, measured the binding energies (BEs) of the ground state (4Fe9/2) and the excited state (4Fe7/2) of the Os^- ion to be 1.07780(12) eV and 0.553(3) eV, respectively. These values are consistent with those calculated using Relativistic Configuration Interaction (RCI) calculations [2]. Here we have calculated the BEs for the ground state and the two excited states of the Os^- ion using our recent complex angular momentum (CAM) methodology [3] and obtained the BEs of 1.910, 1.230 and 0.224 eV, respectively (see Figure). We conclude that: 1) the measured value of 1.07780(12) eV corresponds to an excited state of Os^- and not to the EA of Os and 2) the EA of Os is 1.910 eV.