Dear users and developers.
I want to compute excitation energies for an organic chromophore in the presence of Rydberg orbitals.
The Rydberg basis is to be centred on the charge centroid of the molecule. So I must place there a dummy
(or a ghost atom?), and then assign to it a set of Rydberg basis functions.
My question is then: how can one specify a dummy centre in Psi4?