Mark R.A. Shegelski

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In low energy electron point source (LEEPS) microscopy, electrons emerge from a point source, propagate as spherical waves, and arrive at a screen. Some electrons scatter off an object, i.e. a cluster of atoms, placed between the source and the screen; others arrive at the screen without scattering. The interference pattern on the screen, an electron(More)
We consider the motion of a cylinder with the same mass and size as a curling rock, but with a very different contact geometry. Whereas the contact area of a curling rock is a thin annulus having a radius of 6.25 cm and width of about 4 mm, the contact area of the cylinder investigated takes the form of several linear segments regularly spaced around the(More)
We compare the exact tunneling time with the quasi-classical tunneling time for idealized potentials. We examine three one-dimensional cases where the potential is chosen to have a simple form. In each case, the exact tunneling time and the quasi-classical time differ significantly. In one case, the two differ in magnitude by a factor of about ten. In(More)
In theoretical low energy electron point source microscopy, simulated holograms are made and used to reconstruct atomic clusters. In previous investigations, simple test clusters were used for convenience. In this paper we explore more realistic structures composed of a single type of atom such as diamond, graphite and Buckminsterfullerene--all of which(More)
We report a new method that gives atomic resolution in the reconstruction of simulated holograms in theoretical low energy electron point source (LEEPS) microscopy, and that uses a screen size that is commensurate with screen sizes used in experimental LEEPS. The method exploits the spherical symmetry in the electron waves emerging from the source. We(More)
We investigate, in one spatial dimension, the quantum mechanical tunneling of an exciton incident upon a heterostructure barrier. We model the relative motion eigenstates of the exciton using a form of the one-dimensional hydrogen atom which avoids difficulties previously associated with 1D hydrogenic states. We obtain probabilities of reflection and(More)
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