Function Of Interatomic Distance Research Articles

Kinetics of homogeneous nucleation on many-component systems

Reiss's classical treatment of the kinetics of homogeneous nucleation in a system containing two chemical components is extended to many-component systems. The formulation is analogous to the pseudostationary state theory of chemical reaction rates with the free energy as a function of the composition of the embryo taking the place of the potential energy as a function of interatomic distances.

Inversion of total cross sections for repulsive ion-atom scattering in the classical regime

With the use of the momentum approximation of classical scattering theory we derive an inversion formula for incomplete total scattering cross sections measured by ion-atom scattering experiments as a function of ion energy. The formula allows direct determination of repulsive interatomic potential functions without the use of trial functions for the potential and, in addition, an estimate of the absolute error as a function of interatomic distance. Analysis of the K +Ar cross sections of Amdur and coworkers shows that for the inversion to be only moderately accurate, the experimental data must cover an energy range of more than an order of magnitude.

The structures of polonium and its compounds—I α and β polonium metal

Employing an isotopic mixture of Po 208 and Po 209 the crystal structures of alpha and beta polonium metal were redetermined from X-ray diffraction powder photographs using monochromatic radiation and a helium atmosphere. Electron distribution curves as a function of interatomic distance were also computed. Previous X-ray data obtained from Po 210 (half-life of 138·4 days), were influenced by the growth of lead at the rate of 0·5 per cent per day and self heating effects. The half-lives of Po 208 and Po 209 are 2·8 years and 103 yr, respectively. The growth rate of lead and the thermal effects from self heating are reduced to four per cent of those in Po 210. Alpha polonium is simple cubic and in space group Pm3m with a = 3·359 ± 0·001 Å and ϱX-ray = 9·142 g/cm 3. Beta polonium is rhombohedral and in space group R 3 m (A10 type) with a = 3·368 ± 0·001 A ̊ , α = 98° 14·4′ and ϱX-ray 9·.392 g/cm 3. The structure of polonium and its relationship to elements in Group VIB are discussed.

The Equation of State of Sodium Fluoride

AbstractThe equation of state of Sodium Fluoride is studied by the method of Verma and Dayal. Theoretical values of thermal expansion are compared with the experimentally measured values and a satisfactory agreement is found upto 530 °K. The theoretical values increase progressively above this temperature. It seems that the parameter ∂ in the exponential interaction term is a function of interatomic distance.