  In this contribution, we present the implementation of a second-order CASSCF
algorithm in conjunction with the Cholesky decomposition of the two-electron
repulsion integrals. The algorithm, called Norm-Extended Optimization,
guarantees convergence of the optimization, but it involves the full Hessian of
the wavefunction and is therefore computationally expensive. Coupling the
second-order procedure with the Cholesky decomposition leads to a significant
reduction in the computational cost, reduced memory requirements, and an
improved parallel performance. As a result, CASSCF calculations of larger
molecular systems become possible as a routine task. The performance of the new
implementation is illustrated by means of benchmark calculations on molecules
of increasing size, with up to about 3000 basis functions and 14 active
orbitals.
