A method to perform modulated structure studies using the program ZMC

The Monte Carlo simulation toolkit ZMC provides a general method for Monte Carlo simulation of disordered molecular displacements, orientations and site occupations. It is part of a suite of programs that allows convenient calculation of three-dimensional reciprocal space diffraction intensities. Such intensities are useful for extensive structure interpretations from diffraction experiments. Some physical properties can also be calculated from the simulation. This article reports the implementation of an integrated ZMC module that facilitates the construction of modulated molecular crystals and allows the corresponding calculation of modulation satellites. Use of the module is explained and examples illustrated. The method is ideally suited for novice treatment of modulated structure features and also as a basic platform to explore complex structure/properties relationships using atomistic simulation techniques.A relatively simple method for users new to modulated structures to implement such structural features in an atomistic Monte Carlo modelling program (ZMC) is described. The relevance and usefulness of such a method are outlined.