Yang, W; Miller, WH, *Block Lanczos approach combined with matrix continued fraction for the S-matrix Kohn variational principle in quantum scattering*,
The Journal of Chemical Physics, vol. 91 no. 6
(1989),
pp. 3504-3508 .
**Abstract:**

*An iterative method is proposed for calculating the S matrix in the Kohn variational approach. Instead of solving the system of linear equations directly, the method consists of a block Lanczos algorithm extended to complex symmetric matrices and a matrix continued fraction procedure. Applications to inelastic and reactive scattering calculations indicate a reasonable rate of convergence. © 1989 American Institute of Physics.*