  We have performed large-scale configuration interaction (CI) calculations
using CIV3for the lowest (in energy) 155 fine-structure levels of aluminum-like
germanium ion. We have calculated the energy levels, lifetimes, oscillator
strengths, and transition probabilities for the electric-dipole allowed and
intercombination transitions among the levels of ground state3s23p(2P)and
higher energy levels of states3s3p2, 3s23d, 3p3, 3s3p3d, 3p23d, 3s3d2,3p3d2,
3d3,3s2(4s, 4p, 4d, 4f) ofGe XX in the LSJ coupling scheme.The present results
include relativistic effects through the Breit-Pauli operator. In order to keep
our calculated energy splittings as close as possible to the experimental and
theoretical results complied by NIST, we attempt to correct the inaccuracies in
the CI coefficients in the wavefunctions, which would lead to inaccuracies in
transition probabilities, by applying a "fine-tuning" technique. Fine-tuning of
the ab initio energies was donethrough adjusting, by a small amount, some
diagonal elements of the Hamiltonian matrix.Comparisons are made with other
available experimental and theoretical results and the accuracy of the present
results is assessed.
