Fluctuations of a large and heavy spherical Brownian particle (B) in an equilibrium fluid are rigorously studied by using two kinds of methods for asymptotic evaluation proposed by Mori; a projection operator method and a scaling method. It is shown that depending on the relative magnitudes of...

Exact numerical solutions are obtained for a two-site doubly degenerate Hubbard model with 2, 3 or 4 electrons to study the effect of intra-atomic exchange interaction on the ground state and the thermodynamic properties. Some properties of macroscopic systems are reproduced qualitatively. The...

Self-diffusion data for methane obtained by the NMR spin-echo technique are reported at −50°, 25° and 50°C over the density range 2 to 27 mol dm−3. The apparatus was calibrated using literature atmospheric pressure tracer data for water and benzene and the calibration was checked using...

In this paper are reported NMR spin-echo measurements of the self-diffusion coefficient of chlorotrifluoromethane at 30°, 50° and 75°C over the density range 3 to 15 mol dm-3. No evidence was found for the type of critical region anomaly recently reported by Duffield and Harris for carbon...

A finite temperature theory is given of the temperature variation of the sound velocity and of the structure factor of liquid helium. The sound velocity is found to decrease slightly as the temperature is increased from absolute zero. The first peak of the structure factor is higher for higher...

In a previous paper we have investigated the relation (dynamical equation of state) among the hydrostatic pressure P, the volume v and the temperature T of an isotropic medium with an arbitrary number, say n, of scalar internal degress of freedom. It has been shown that linearization of the...

In previous articles by Nauenberg and by Niemeijer and Ruijgrok, the renormalization group approach has been used to obtain series expansions for the free energies of certain one- dimensional spin systems. We investigate here the question of whether this method provides a fundamentally new way...

The ground-state energy of a low-density hard-disk Fermi gas is analysed with a variational calculation and with a perturbation-theory summation. The results of the analyses for the first two terms in the energy, the Fermi energy and the analogue of the Lenz interaction energy, agree with each...

It is shown how the Percus-Yevick and convolution-hypernetted-chain approximations for dense fluids of linear molecules can be brought into practically applicable forms by using cartesian tensor formalism and pertubation theory. The possibility of expanding the intermolecular potential and the...

The general formulae derived in an earlier article are applied to some special cases, viz., the Fokker-Planck or diffusion limit, the linear case, and the Malthus-Verhulst equation with random coefficients.