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Series

1990

Physics Publications

Articles 1 - 6 of 6

Full-Text Articles in Physics

Erratum: Eigenvalues And Retardation Effects In The N = 10 States Of Helium (Journal Of Physics B: Atomic, Molecular And Optical Physics (1989) 22 (L651-L657)), Gordon W. F. Drake Jan 1990

Erratum: Eigenvalues And Retardation Effects In The N = 10 States Of Helium (Journal Of Physics B: Atomic, Molecular And Optical Physics (1989) 22 (L651-L657)), Gordon W. F. Drake

Physics Publications

No abstract provided.


An Alternative Proof Of Some Relations Between Hydrogenic Matrix Elements, R. A. Swainson, Gordon W. F. Drake Jan 1990

An Alternative Proof Of Some Relations Between Hydrogenic Matrix Elements, R. A. Swainson, Gordon W. F. Drake

Physics Publications

A relationship between certain integrals of the product of two Laguerre polynomials is obtained. It is shown how this relationship, together with two known Hankel transforms, allows for an alternative derivation of some relations between matrix elements of r k for hydrogenic ions. A further relation, involving matrix elements of logarithmic functions, is obtained in a similar manner. © 1990 IOP Publishing Ltd.


Expectation Values Of Rp For Arbitrary Hydrogenic States, Gordon W. F. Drake, R. A. Swainson Jan 1990

Expectation Values Of Rp For Arbitrary Hydrogenic States, Gordon W. F. Drake, R. A. Swainson

Physics Publications

Expectation values of rP for an arbitrary nl hydrogenic state are expressed in terms of state-independent coefficients that are determined by a simple recursion relation. Explicit results are given for negative P down to -16 and, by an algebraic transformation, for positive P up to 13. Closed-form expressions are obtained for the coefficients of the two highest-order terms in l multiplying each power of n. The result is an asymptotic expression valid for each P and sufficiently large l. © 1990 The American Physical Society.


Bethe Logarithms For Hydrogen Up To N=20, And Approximations For Two-Electron Atoms, Gordon W. F. Drake, R. A. Swainson Jan 1990

Bethe Logarithms For Hydrogen Up To N=20, And Approximations For Two-Electron Atoms, Gordon W. F. Drake, R. A. Swainson

Physics Publications

Bethe logarithms accurate to 14 or 15 places to the right of the decimal are tabulated for all states of hydrogen up to n=20. Approximation methods for Rydberg states of two-electron atoms are discussed. © 1990 The American Physical Society.


Molecular View Of The Interfacial Adhesion In Aluminum‐Silicon Carbide Metal‐Matrix Composites, B. K. Rao, Puru Jena Jan 1990

Molecular View Of The Interfacial Adhesion In Aluminum‐Silicon Carbide Metal‐Matrix Composites, B. K. Rao, Puru Jena

Physics Publications

The binding energies, electron charge transfer,bond lengths, and core level shifts of Al‐Al, Al‐Si, Al‐C, and Si‐C dimers have been calculated self‐consistently using the linear combination of atomic orbitals‐molecular orbital theory. The exchange interactions are treated using the unrestricted Hartree–Fock theory and correlation corrections are included through the Möller–Plesset perturbation scheme up to fourth order. The results are used to understand the nature and strength of bonding at the interface of Al and SiC crystals. The strong bonding of Al‐C dimers compared to Al‐Al and Al‐Si is shown to be responsible for the aluminumcarbide formation at the interface. The charge …


Effect Of Size And Dimensionality On The Magnetic Moment Of Transition Metals, Feng Liu, S. N. Khanna, P. Jena Jan 1990

Effect Of Size And Dimensionality On The Magnetic Moment Of Transition Metals, Feng Liu, S. N. Khanna, P. Jena

Physics Publications

The effect of size and dimensionality on the magnetic moments of Fe, Co, and Ni have been studied theoretically by confining the atoms to various structural forms such as chains, surfaces, and thin films. The size of these systems is controlled by limiting the number of atoms. A new first‐principles theory is developed that enables us to study the electron spin density of states and moments of atoms in clusters containing two to a few thousand atoms. The theory is based upon the elementary principles governing the tight binding and linear combination of atomic orbitals formulations. It contains no adjustable …