The distance dependence and spatial distribution of the molecular quadrupole moments of P2, S2 and Cl2

The quadrupole moments (Θ) of the molecules P₂, S₂ and Cl₂ have been computed at the SCF, CASSCF and CASSCF + 1 + 2 levels of theory, using augmented correlation consistent basis sets. The convergence of Θ as a function of basis set and level of theory is discussed. The variation of Θ from the separated atoms to the equilibrium region is reported. Θ is written as the sum of a sigma and pi contribution, and inaccuracies in the SCF values for P₂ and S₂ are due to the poor representation of the pi system in the SCF theory. A reference state dependent quadrupole moment density, - ½(3cos² θ- 1)r ²δη(r; R), is defined whose integral is the mole2 cular quadrupole moment, and the spatial distributions of the density and its relationship to the density difference δη(r; R) are examined.     

An accurate program for radiation modelling in the desigh of high-tempersature furnaces

The zone method is well established for determining radiativeheat transfer. It has been used successfully in simple geometries.However the task of determining the required exchange areashas limited its use in more geometrically complex enclosures.In this paper, a computer program, RADEX, is descrilxd. Thisprogram will calculate direct and total exchange areas usinga Monte Carlo method for enclosures with complex geometries.Some results from a validation study of RADEX are given. Finally,as an illustration of its potency as a design tool, the resultsof a comparative study of nine different designs of radianttube furnace are given.     

A SURVEY OF SOME IDEAS FOR ACCELERATORS USING LASER LIGHT

Many Suggestions have been made for accelerating particles in the intense fields associated with laser light. Those which rely on direct interaction with the laser field in vacuo (as opposed to acceleration in a plasma medium) are examined and their fundamental limitations discussed. Three schemes are considered, the first of these utilizes slow electromagnetic waves near a surface, the second relies on a fast electromagnetic wave with "phase jumps" and the third used parametric interaction with particles moving on a modulated orbit.     

Approaches to the space-time modelling of infectious disease behaviour

A new approach to the space-time modelling of infectious diseasesis considered. A modulated heterogeneous Poisson process withintensity defined as a function of a two-dimensional susceptibilityfield is proposed. The model is fitted to a measles epidemicusing a proportional hazards approximation.