Perturbation theory. A reference on computational aspects

[boufer <boufer { *at * } cennas.nhmfl.gov>]

 Greetings all,
 I wonder if anybody coud suggest a good reference regarding the
 computational aspects of perturbation theory. As a matter I am a little
 confused as regard the application of such a procedure using the results
 of a Hartree-Fock calculation.
 Let me get more explicit :
 Let's assume for simplicity that one has a one-electron perturbation
 H' = Sum_i h(i). Then, if my knowledge in this perturbation "business"
 is right, the function~(first order correction) Psi' is expanded as a
 linear combination of the determinants corresponding to the ground
 state, first "excited" determinant, second "excited"
 determinanant, ...
 This is the RSPT.
 As a consequence of this, the second order correction of the energy
 should involve only the first "excited" determinant~(for a two
 particle
 pertubation as in MP2 for instance we will use only the second
 "excited"
 determinant.)
 We know that the above expansion yields an exact answer if the basis set
 is complete.
 The question is : Is there any procedure allowing us to choose the basis
 functions in order to get accurate results though the size of the basis
 is finite ?
 Thanks for your time and Help.
 --
 Ahmed