  Multicentric integrals that involve a continuum state cannot be evaluated
with the usual quantum chemistry tools and require a special treatment. We
consider an initial molecular bound state described by multicenter spherical or
cartesian Gaussian functions. An electron ejected through an ionization process
will be described by an oscillating continuum wavefunction that enters the
matrix element necessary for cross section calculations. Within a monocentric
approach, we have recently shown how such integrals can be evaluated
analytically by using a representation of the continuum state by a set of
complex Gaussian functions. In this work we tackle the multicentric situation.
The method, developed in either spherical or cartesian coordinates, and
validated by numerical tests, makes use of existing mathematical tools extended
to the complex plane.
