Direct methods

Direct Methods for Surfaces

This paper reviews recent progress in the application of Direct Methods to solve surface structures using surface X-ray or transmission electron diffraction data. The basic ideas of (crystallographic) Direct Methods are presented, as well as the additional problems posed by trying to apply them to surfaces and how they connect to the mathematical theory of projections. Surface crystallography n...

Examination of PbCO3 solubility using direct and competitive chelation methods

A Survey of Direct Methods for Solving Variational Problems

This study presents a comparative survey of direct methods for solving Variational Problems. Thisproblems can be used to solve various differential equations in physics and chemistry like RateEquation for a chemical reaction. There are procedures that any type of a differential equation isconvertible to a variational problem. Therefore finding the solution of a differential equation isequivalen...

EDM 1.0: electron direct methods.

A computer program designed to provide a number of quantitative analysis tools for high-resolution imaging and electron diffraction data is described. The program includes basic image manipulation, both real space and reciprocal space image processing, Wiener-filtering, symmetry averaging, methods for quantification of electron diffraction patterns and two-dimensional direct methods. The progra...

Crystallographic direct methods for surfaces

A brief review is given of the status of crystallographic direct methods for solving surface structure problems. The basic concepts of using the a priori information that the scattering comes from atoms to generate self-consistent equations and statistical constraints upon the phases are described. The use of a genetic algorithm to perform a search over possible phases is then discussed. Finall...