Chemical Bonding between Cu and OxygenCopper Oxides vs O₂ Complexes:  A Study of CuO_x (x = 0−6) Species by Anion Photoelectron Spectroscopy

Abstract

An extensive photoelectron spectroscopic study on the CuO x - (x = 0−6) species is presented. The photoelectron spectra of these species are obtained at four detachment photon energies: 2.33, 3.49, 4.66, and 6.42 eV. The spectra of the copper atom are included to show the dependence of the detachment cross sections on the photon energies. An intense two-electron transition to the 2P excited state of Cu is also observed in the 6.42 eV spectrum of Cu-. For CuO-, we observe an excited state of the anion, as well as photodetachment transitions to charge transfer excited states of CuO (Cu2+O2-). Six transitions are observed for CuO2 - at 6.42 eV, revealing all six valence molecular orbitals of the linear OCuO molecule. CuO3 - is observed to undergo photodissociation at 3.49 eV to give an internally hot CuO- plus O2. It is shown to have an OCuO2 type of structure, and its electronic structure can be viewed to be due to that of CuO perturbed by an O2. For CuO4 -, two isomers are observed. One of them undergoes photodissociation at 3.49 eV, and it is shown to be a Cu/O2 complex, Cu(O2)2 -. The second isomer yields spectra identical to that of the linear OCuO- with a slight energy shift and is concluded to be an OCuO- solvated by a very weakly bonded O2, (OCuO-)O2. CuO6 - is shown to exhibit similar behaviors as CuO4 - with a Cu/O2 complex, Cu(O2)3 -, and an O2-solvated CuO2 -, (OCuO-)(O2)2. The CuO5 - spectra are observed to be similar to that of CuO3 -, and it is shown to be due to a CuO3 - solvated by an O2, (OCuO2 -)O2.

Structures and Electronic Properties of Cu3On (n = 1–6) Clusters using ab initio Monte Carlo Simulations

“…Experimental data for the EAs had been studied for CuO x (x = 0-6). 23 Our calculated EA (1.37 eV) of CuO is in good agreement with the experimental EA (1.53 eV). Even though the EAs in the experiment are oscillating as the cluster size increases, our calculated ones are not.…”

Density functional theory study of the structures and stabilities of CuO and CuO3

“…From the B3LYP values of Table II, one can see that the adiabatic (vertical) ionization potentials of the most stable 3 A (II) state and the next most stable 1 A 1 (I) state of CuO − 3 species are predicted to be 3.00 (3.25) and 3.13 (3.38) eV, respectively, which are comparable to the observed 3.19 and 3.39 eV [9]. Thus, the most stable 3 A (II) state and the next most stable 1 A 1 (I) state of CuO − 3 may be tentatively assigned to the ground state and the first excited state of CuO − 3 observed in the experiment [9], respectively. We must note that in the original work, the 3.19-eV structure was tentatively assigned to a side-on structure (I) [9].…”

“…Many theoretical and experimental studies have been directed at CuO and CuO 2 [3 -8]. In a recent anion photoelectron spectroscopy study [9], a new CuO − 3 molecule was observed for the first time. CuO − 3 contains a CuO − bonded to an O 2 molecule and dissociates at 3.49 eV into CuO − and O 2 .…”

“…CuO − 3 contains a CuO − bonded to an O 2 molecule and dissociates at 3.49 eV into CuO − and O 2 . A minor isomer, Cu(O 3 ) − , was also generated by the plasma reactions between the laser-vaporized copper atoms and O 2 [9]. The isomers of CuO 3 could be classified into two kinds.…”

Photoelectron Spectroscopy of Nickel, Palladium, and Platinum Oxide Anions

“…Experimental data exist for ONiO and OPtO (14,15,39), and a few theoretical studies have calculated molecular structures and electronic properties (26,29,40). Several photoelectron spectroscopic studies have been carried out on similar metal molecules, including CuO − (41,42), (45). A major complication associated with analysis of these metal oxide species arises from the failure of a single-configuration view of the metal oxide to provide a useful zero-order picture of the electronic state (46).…”