  This paper presents a brand new methodology to deal with isotopic fine
structure calculations. By using the Poisson approximation in an entirely novel
way, we introduce mathematical elegance into the discussion on the trade-off
between resolution and tractability. Our considerations unify the concepts of
fine-structure, equatransneutronic configurations, and aggregate isotopic
structure in a natural and simple way. We show how to boost the theoretical
resolution in a seemingly costless way by several orders of magnitude with
respect to the already very efficient algorithms operating on isotopic
aggregates. We also develop an effective new way to obtain the important peaks
in the most disaggregated isotopic structure localised in a precise region in
the mass domain.
