RECURSIVE INTERMEDIATE FACTORIZATION AND COMPLETE COMPUTATIONAL LINEARIZATION OF THE COUPLED-CLUSTER SINGLE, DOUBLE, TRIPLE, AND QUADRUPLE EXCITATION EQUATIONS

The nonlinear CCSDTQ equations are written in a fully linearized form, via the introduction of computationally convenient intermediates. An efficient formulation of the coupled cluster method is proposed. Due to a recursive method for the calculation of intermediates, all computational steps involve the multiplication of an intermediate with a T vertex. This property makes it possible to express the CC equations exclusively in terms of matrix products which can be directly transformed into a highly vectorized program.