We present a new technique to accelerate the convergence of the folded spectrum method in empirical pseudopotential band edge state calculations for colloidal quantum dots. We use bulk band states of the materials constituent of the quantum dot to construct initial vectors and a preconditioner. We apply these to accelerate the convergence of the folded spectrum method for the interior states at the top of the valence and the bottom of the conduction band. For large CdSe quantum dots, the number of iteration steps until convergence decreases by about a factor of 4 compared to previous calculations.
Vömel, C., Tomov, S. Z., Wang, L. W., Marques, O. A., & Dongarra, J. J. (2007). The use of bulk states to accelerate the band edge state calculation of a semiconductor quantum dot. Journal of Computational Physics, 223(2), 774–782. https://doi.org/10.1016/j.jcp.2006.10.005