Showing papers on "Valency published in 1972"

A Grammar of Aspect: Usage and Meaning in the Russian Verb

Abstract: Preface 1. The category of aspect 2. Aspect and form 3. Aspectual pairs 4. Past tense 5. Present and future tenses 6. Multiple action 7. Modals - I. Imperative 8. Modals - II. Infinitive and other constructions 9. Gerunds and participles 10. Verbs of motion 11. Conclusion Bibliography Russian index English index.

Note on the structure and occurrence of ytterbium transition metal compounds

Abstract: The binary systems Yb-Ni, Yb-Co and Yb-Fe have been studied by X-ray diffraction methods. The number of compounds observed in these systems is six, three and two, respectively. For most of these compounds the crystal structure and the lattice parameters are given. Compared with other rare-earth transition metal systems the investigated systems contain relatively few compounds. This is discussed in terms of a size-dependent stability of the structures and a variable valency of the ytterbium atoms.

Study of the electronic structure of molecules. XV. Comments on the molecular orbital valency state and on the molecular orbital energies

Abstract: The valency state (vs) concept is analyzed in the Hartree–Fock approximation. A valency state “standard” is defined for atoms at infinite separation. A molecular orbital valency state (Movs) is defined from a partitioning technique (bond energy analysis) previously introduced for the Hartree–Fock molecular wave functions. The Movs for a given atom in a molecule is much higher in energy than the vs and its energy varies from molecule to molecule depending on the exact field of the surrounding atoms. The examples selected in the discussion are the CH4 CH3F, CH2F2, CHF3 and CF4 molecules. An analysis of the orbital energies is then given in terms of the bond energy. The importance of the rearrangement effects following ionization of inner shell electrons (simulation of ESCA type experiments) is illustrated with computations of the positive ion for methane and its fluoroderivatives. It is concluded that rearrangement following ionization from inner shells is as important as rearrangements following ionization from valency electrons. A direct consequence is that the orbital energies should not be equated to the inner shell ionization potentials. The computation of such ionization potentials agrees to about 99.5% with ESCA data, when the energy of both the neutral and ionic species are computed; the use of the orbital energies limits this agreement to about 95%.

Glass‐Forming Ability vs Local Order and Covalent Character in the As–Te System

Abstract: An experimental study of the constitution of the As–Te glasses has been carried out, using glass‐forming‐ability measurements, high‐angle diffraction, differential thermal analysis, and other thermodynamic determinations. Evidence is definitely given for a difference of valency between crystalline and glassy states. A model is suggested for the structural units in the glass and for the modifications induced by an excess of arsenic or tellurium with respect to the critical As2Te3 composition.