n-Beam lattice images. V. The use of the charge-density approximation in the interpretation of lattice images

The simple infinite-aperture charge-density approximation to lattice imaging is extended to include the effects of finite aperture and objective-lens spherical aberration. Images computed using these approximations are compared with images computed by the accurate N-beam technique and with experiment in order to establish the bounds of applicability of the extended-charge-density approximations.