Stable and efficient algorithms for Xα multiple scattering calculations
John Wiley & Sons, Inc.
Solutions to some practical problems that arise in multiple scattering calculations on large molecules are discussed. (1) Numerical instabilities near the zero of energy can be removed by rescaling the secular matrix. (2) The calculation of structure factors can be made much more efficient by the application of symmetry projection operators. (3) An energy search procedure is described that ensures that no states are inadvertently neglected. Test calculations incorporating these changes illustrate the improved numerical stability, and show decreases in computation time of 30–60%, when compared to previous codes. The procedures suggested here are applicable to both relativistic and nonrelatitistic calculations.
D.A. Case and C.Y. Yang, “Stable and efficient algorithms for Xα multiple scattering calculations,” International Journal of Quantum Chemistry 18, 1091-1099 (1980).