A single configuration model containing nonorthogonal magnetic orbitals is developed to represent the important features of the antiferromagnetic state of a transition metal dimer. A state of mixed spin symmetry and lowered space symmetry is constructed which has both conceptual and practical computational value. Either unrestricted Hartree–Fock theory or spin polarized density functional theory, e.g., Xα theory, can be used to generate the mixed spin state wave function. The most important consequence of the theory is that the Heisenberg exchange coupling constant J can be calculated simply from the energies of the mixed spin state and the highest pure spin multiplet.

Valence bond description of antiferromagnetic coupling in transition metal dimers

Core-level binding-energy shifts at surfaces and in solids

Etude par spectroscopie de photoelectrons de la degradation superficielle de FeS2, CuFeS2, ZnS et PbS a l'air et dans l'eau

Core-electron binding energies for gaseous atoms and molecules

The auger parameter, its utility and advantages: a review

Gas phase photoelectron spectra of sodium, potassium, rubidium, cesium, and magnesium have been obtained with AlKα radiation. The binding energies measured are: Na 1s (1079.1 eV), K2p (303.2 eV, 300.5 eV), Rb 3p (254.3 eV, 245.4 eV), Cs 3d (745.8 eV, 731.8 eV), and Mg1s (1311.5 eV). Experimental and theoretical values from the literature have been compared with our results. The free atom binding energies were found to be greater than the comparative solid state binding energies; the differences being: Na 5.1 eV, K 3.6 eV, Rb 3.4 eV, Cs 3.4 eV, and Mg 4.8 eV. The multielectron excitation satellites present in the spectra of these atoms are also discussed.

Free atom core binding energies from X‐ray photoelectron spectroscopy. II. Na, K, Rb, Cs, and Mg

An XPS study of the oxidation of pyrite and pyrites in coal

Inner shell excitation and ionization of the monohalobenzenes

The Na(1s) binding energy in atomic sodium has been determined by x‐ray photoelectron spectroscopy to be 1079.1(±0.1) eV. The spectrum exhibits a satellite 8.4 eV to the high binding energy side of the primary peak with a relative intensity of 19(±1) %. It is assigned to a 3s→4s excitation accompanying ionization. Ab initio ’’ΔSCF’’ calculations are in good agreement with experiment for both the separation and intensity of the satellite. The unusually large intensity of the shakeup peak compared to those found in the inert gases is discussed. Theoretical Na(1s) binding energies in the series Na, Na2, and Na3, suggest that ∼90% of the binding energy shift between the free atom and the metal (5.1 eV) is due to the extraatomic relaxation in the metal.

The x-ray photoelectron spectrum of atomic sodium

X‐ray photoelectron spectra of the Ti 2p and 3p and halogen core levels from titanium tetrahalide vapors have been obtained. Satellites are observed at higher binding energies than the halogen core levels as well as the titanium levels. The origin of these satellites is discussed by comparison with published data on octahedral Ti(IV) compounds. It was also observed that the separation of the Ti 2p spin–orbit doublet in TiF4 was lower than the separations observed in the other three molecules (5.2 eV in TiF4 as compared to 6.1 eV).

B. Wallbank

Papers

Free atom core binding energies from X‐ray photoelectron spectroscopy. II. Na, K, Rb, Cs, and Mg

An XPS study of the oxidation of pyrite and pyrites in coal

Inner shell excitation and ionization of the monohalobenzenes

The x-ray photoelectron spectrum of atomic sodium

X‐ray photoelectron spectroscopy of titanium tetrahalide vapors