A systematic study is made of the average local velocity field acting at a selected particle in a fluid suspension. The flow disturbance due to a single particle is analyzed in terms of force multipoles. The theory is developed in close analogy to that for the corresponding problem of the local...

In this paper a low-energy-electron diffraction theory for molecular crystals is established. The possibility of creating Frenkel excitons by the incident low-energy electrons is taken into account. The whole formalism is based on a set of diagram rules, which facilitates the evaluation of the...

In the framework of our generalization of the Debye-Bueche theory for the frictional properties of dilute polymer solutions we study the intrinsic viscosity. A careful definition of the intrinsic viscosity for polymers with spherically symmetric density distribution is given. The equations are...

Some of the influences Julian Schwinger has had on condensed matter physics are discussed. The first part rapidly summarizes the language and methods he introduced to describe physical systems exactly and to approximate their properties systematically. The significance of these methods and the...

The dynamics of a v-dimensional Fermi lattice system with a bilinear hamiltonian is derived in a very simple and natural way. Moreover the thermodynamics of this linear system is treated by means of the so-called K.M.S.-equilibrium condition. Some words are devoted to ergodicity. As an example...

A monolayer of 4He atoms is treated as a system of hard-sphere bosons in a thin film geometry, with a finite thickness. The method of pseudopotential is used to calculate first the energy spectrum, and then the Helmholtz free energy and other thermodynamic functions of the system. It is found...

Exact and simple expressions are obtained for the translational part of absorption spectra in rare gas mixtures using the following model. The induced electric dipole moment function is represented by a gaussian while for the intermolecular potential a hard core plus a soft repulsive tail is...

The previous results for the scattered field of two plane monochromatic sound waves is shown to possess a singularity as the wave vectors become equal. A new solution which removes this singularity is presented.