Partitioning and the Remainder Term

The most recent of the publications to question the applicability of the low order theory studies is authored by Schaefer and his co-workers who ask the question Is Moller-Plesset perturbation theory a convergent ab initio method These authors write 

The tacit assumption behind chemical applications of MPn theory is that the perturbation series is convergent... 

They quote the conclusion of earlier work by Dmming and his co-workers  

The current study, combined with other recent studies, raises serious doubts about the use of Moller-Plesset perturbation theory to describe electron correlation effects in atomic and molecular calculations. 

The work of Schaefer et al.f along with earlier work by Duiming et al, 83 86 by 

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