For the binary division of electrically charged liquid drops a (pseudo) saddle point configuration is considered consisting of two spheres of radii r1 and r2, a distance α(r1 + r2) apart.Computation of surface energy and Coulomb energy terms shows that an asymmetric configuration, i.e., r1 ≠ r2 is energetically favored for all values of the fissionability parameter [Formula: see text], where x is defined as x = Q2/16πR3γ for the original drop with charge Q, radius R, and surface tension γ. Minimization of the energy terms requires a charge transfer directed towards the smaller sphere.Uniform, but not necessarily equal, surface charge is assumed for the two-sphere configuration. A more exact solution involving image charges gives very similar results.The present results for sphere separations α = 1 to α = ∞ confirm previous work in which a value of α = ∞ only was considered.

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The division of an electrically charged drop into two drops is considered. It is shown that for symmetric division the surface energy and electric energy of the final state of the system are at a minimum only if the surface charge Q on the drop of radius R and surface tension γ is[Formula: see text]If, however, Q2 is a fraction of this value, asymmetric division leads to a minimum of the final energy terms.Results of the photographic observation of the division of charged water drops in paraffin oil support the theory, i.e. asymmetric division is observed. Symmetry is approached for higher charges on the drops.For the division of uniformly volume-charged drops the theory predicts symmetric division.Theoretical energy–asymmetry plots bear a strong resemblance to fission-yield curves. The validity of the application of the theory to the observed asymmetry in nuclear fission is discussed.

The current status of photoelectron-diffraction studies of surface structures is briefly reviewed, and several recent developments and proposals for future areas of application are then discussed. The application of full-solid-angle diffraction data, together with simultaneous characterization by low-energy electron-diffraction and scanning-tunneling microscopy, to epitaxial growth is considered. Several new avenues that are being opened up by third-generation synchrotron-radiation sources are also considered. These include photoelectron diffraction from surface and interface atoms, the possibility of time-resolved measurements, and circular dichroism in photoelectron angular distributions. The addition of spin to the photoelectron-diffraction measurement is also considered, and can be achieved either through core-level multiplet splittings or by circular-polarized excitation of spin–orbit-split levels. This last development should make it possible to study short-range magnetic order, perhaps even in a holographic fashion.