Trapped electrons in substoichiometric MoO3 observed by X-ray electron spectroscopy

Substoichiometric amorphous thin films of MoO₃ in both the transparent and absorptive forms have been studied by X-ray electron spectroscopy. The transparent films can be colored blue (absorptive) electrically or by UV irradiation. The electron distribution curve of the blue film exhibits a small band near the Fermi edge which is absent in the transparent sample. This new band is attributed to electrons trapped in positively charged anion vacancies in the substoichiometric MoO₃ lattice. This model provides an interpretation of the electrical conductivity and color of the films.     

Detection of surface atoms by energy analysis of scattered primaries and recoiled secondaries from CsBr under Ar+ and Ar+ bombardment

Time-of-flight (TOF) and electrostatic sector analysis (ESA) have been used to measure particles scattered and sputtered by direct recoils and surface recoils during 3 keV Ar⁺ and 6 keV Ar²⁺ bombardment of CsBr at forward and backscattering angles. Charge fractions of scattered argon and recoiling surface atoms are obtained. Hydrogen and oxygen surface impurities are detected predominantly as directly recoiled neutrals.     

Kinetic energy dependence of the reactions of N+ and N2+ with molybdenum

Mass-selected beams of N⁺ and N₂⁺ in the energy range 5–50 eV react with molybdenum to produce a surface nitride. The relative reaction cross section for N⁺ reaction is higher than that of N₂⁺ in the range 5–25 eV and N₂⁺ exhibits a reaction threshold near 7 eV. The N₂⁺ threshold suggests collisional dissociation prior to reaction.     

Molecular rearrangement and cluster formation in the secondary ion mass spectra (SIMS) of fluoride salts

Secondary ion clusters with mass greater than 700 amu, e.g., K(KF)₁₂⁺ and up to 27 atoms, e.g., Na(NaF)₁₃⁺, have been observed in the static SIMS spectra of MF (M = Li, Na, K), NaBF₄, and KPF₆. The long series of detected cluster ions of the type M(MF)_n⁺ indicates that there is a high degree of stability associated with these clusters. The observation of such clusters in the NaBF₄ and KPF₆ spectra suggest that there is significant molecular rearrangement occurring in the secondary ion emission process from such salts. The secondary ion Intensities provide a crude fit to the Saha-Eggert equation, yielding an electron temperature of ~12,000 K. The data are consistent with the plasma model of surface ionization in which rearrangement and cluster formation occur in the plasma.     

Molecular photoionization cross-sections and their dependence on excitation energy

A general formula for the photoionization cross-section of a linear molecule in terms of atomic subshell cross-sections and diffraction effects is given. Example calculations are carried out for line intensities of CO and N₂ as a function of incident photon energy from threshold up to the soft X-ray region. The importance of associating CNDO coefficients to orthogonal Slater AO's is pointed out. General rules for dependence of photoionization cross-sections on excitation energy are discussed.