The 4d relative photoabsorption cross section of cesium has been observed to change dramatically in appearance along the isonuclear sequence Cs through Cs. In each case, discrete structure is observed below threshold and for Cs through Cs, a giant dipole 4d→« f resonance is also present above threshold. Between Cs and Cs, there is a striking change, with much of the oscillator strength availabl...

Studies of the physical parameters that influence the single scattering properties of a size distribution of small particles in random orientation are fundamental in understanding the origin of the observed dependence of the scattering matrix elements on the scattering angle. We present results of extensive calculations of the single scattering matrices of small nonspherical particles performed...

Dual-polarisation radar measurements provide valuable information about the shapes and orientations of atmospheric ice particles. For quantitative interpretation of these data in the Rayleigh regime, common practice is to approximate the true ice crystal shape with that of a spheroid. Calculations using the discrete dipole approximation for a wide range of crystal aspect ratios demonstrate that...

This work presents a highly-optimised computational framework for the Discrete Dipole Approximation, a numerical method for calculating the optical properties associated with a target of arbitrary geometry that is widely used in atmospheric, astrophysical and industrial simulations. Core optimisations include the bit-fielding of integer data and iterative methods that complement a new Discrete ...

Over the past three decades, the dipole approximation has facilitated a basic understanding of the photoionization process in atoms and molecules. Advances in gas-phase photoemission experiments using synchrotron radiation have recently highlighted nondipole effects at relatively low photon energies while probing the limits of the dipole approximation. Breakdowns in this approximation are manif...

67 O ne of the main functions of graphic displays is drawing straight lines. To draw lines quickly, the speed of the applied algorithm is critical. The following three different approaches exist: I discrete differential analysis (DDA), introduced by Bresenham, 1 I combinatory analysis, 2 and I linguistic methods. 3,4 The most famous approach remains the DDA, since extended by N-step algorithms....