Tetrahedral atom ordering in sodium feldspars: a Monte Carlo study

The substitutional disorder of Al and Si atoms in sodium feldspars has been analyzed by Monte Carlo simulations. To study the influence of non-configurational degrees of freedom on the order—disorder process, we performed simulations allowing atom displacements along with interchanges between Al and Si atoms. It is found that the coupling between configurational and displacive degrees of freedom is important to explain the order—disorder properties of this compound from a microscopic point of view.