Coherent state formulation of multiconfiguration states

The theory of vector coherent states is applied to multiconfiguration states that are given a complex parametrization, based on the underlying special linear group. Using the time-dependent variational principle, equations of motion for such states are formulated as evolution equations in a generalized phase space. The classical Hamiltonian for these equations is given in terms of the reduced first- and second-order density matrices, which can be expressed in terms of partial derivatives with respect to the group parameters of the overlap kernel. The multiconfiguration self-consistent-field (MCSCF) and configuration interaction (CI) equations arise as special cases of these equations. Using the coherent state formulation we obtain very compact and numerically efficient expressions for the time-dependent quantum mechanical description of chemical reactions.