Infinite Band Research Articles

The magnetic susceptibility of virtual bound state alloys

The static and dynamical longitudinal and transverse magnetic impurity spin susceptibilities of the nondegenerate virtual bound state model are calculated as functions of temperature, magnetic field, virtual level width and for arbitrary separation of the quasibound level from the Fermi surface of an infinite structureless conduction electron band. Within this exactly solvable quantum-mechanical model problem the static spin susceptibilities remain finite at zero temperature and follow power law behaviour for low temperatures; at higher temperatures a Curie-Weiss law is obeyed. The dynamical susceptibilities are shown to exhibit interesting temperature, magnetic field and frequency dependent variation; in particular a continuous transition between quantum-mechanical and classical domains is analytically tractable. The longitudinal resonance lineshape is found to deviate from the Lorentzian Bloch equation form but reduces to such in the classical high-temperature regime. For the transverse absorption spectrum this rate equation description may also be obtained by freezing the fluctuating pseudospin with a strong external magnetic field. The impurity spin relaxation rates are finite and approach a constant at high temperatures.

Electronic structure of silanes in the semi-empirical equivalent orbital method

The problem of the prediction of the valence IPs for silanes is considered. It is shown that the data on the silicon band structure combined with the photoelectron spectra of SiH4, and Si2H6 permit to obtain the parameter scale, which includes all the nearest neighbour, second neighbour and the main third neighbour interaction parameters. Using the derived parameter scale the vertical ionization potentials of Si3H8, SiH(SiH3)3, Si(SiH3)4, the infinite polysilane valence band structure and the inner a1g level for disilane are calculated. All the calculated levels are located above − 20 eV and are expected to be measurable by the He (I) photoelectron spectroscopy.

Distortion of the semi-infinite solid due to transient surface heating

A method is described for finding the normal displacements of the surface of a semi-infinite solid, subjected to arbitrary, transient surface heating. Analytical expressions are derived for the displacements due to instantaneous and continuous point and line heat sources and these can be integrated to produce the solutions to particular problems. The method is illustrated by application to uniform heating over a circular area and over an infinite band. Solutions are also obtained for the displacements due to point and line doublets which can be used to solve problems in which the temperature distribution at the boundary plane is defined. These results permit the reduction of problems in the non-isothermal contact of solids to equivalent isothermal problems.

Time-independent temperature field in a band and a layer under mixed boundary conditions

The time-independent temperature field is determined for an infinite band and a layer under mixed boundary conditions.

Convective diffusion in an infinite band

A solution of the mixed boundary-value problem in the form of a generalized function represented by a contour integral is obtained for the stationary equation of convective diffusion.

Some Aspects of Lightning Surges on Power Systems and Their Suppression

The paper points out that lightning surges contain an infinite band of frequency components and for this reason, the behavior of a system to surges depends on its impedance characteristics over a wide range of frequencies. A capacitive-inductive suppression device is suggested and design details and test results given. This device is most effective for short-duration steep-sided surges. At present, it seems practicable for lower voltage circuits but if cheaper capacitors can be constructed, it also could be used for higher voltages.