Patent ID: 6106562
Filing Date: 2000-08-22
Classification: G16C

Abstract:
A method for displaying the structure of a material comprising the steps of:(A) inputting data into a computer system regarding the atomic composition, atomic positions, and excitation state of the material and the environment in which the material resides;(B) selecting an expression for the wavefunction describing the electrons of the material, said expression being a product of component wavefunctions, each of the component wavefunctions including a linear combination of plane waves, each plane wave being characterized by a spatial frequency and direction and being multiplied by a wavefunction parameter;(C) iteratively determining values for the wavefunction parameters by means of a programmed computer by:(I) changing the wavefunction parameters for one of the component wavefunctions while holding the wavefunction parameters of the remaining component wavefunctions constant by iteratively performing the steps of:(a) calculating values for the components of the gradient of the energy of the electrons of the material with respect to the wavefunction parameters of the wavefunction component being changed;(b) conditioning the values calculated in step (C) (I) (a) by reducing some of those values relative to others of those values, the values which are reduced corresponding to plane waves having higher spatial frequencies than the spatial frequencies corresponding to the values which are not reduced;(c) determining from the conditioned values obtained in step (C) (I) (b), a set of changes to the wavefunction parameters of the wavefunction component being changed; and(d) forming a changed set of wavefunction parameters for the wavefunction component being changed from the set of changes determined in step (C) (I) (c);(II) performing step (C) (I) for each of the other component wavefunctions; and(III) repeating steps C (I) and C (II) until the wavefunction parameters satisfy a predetermined criterion;(D) determining a structure for the material using the wavefunction expression selected in step (B) and the wavefunction parameters determined in step (C); and(E) displaying the structure determined in step (D).