CRASY: correlated rotational alignment spectroscopy reveals atomic scrambling in ionic states of butadiene.

We use correlated rotational alignment spectroscopy to reveal atomic scrambling in transient ionic states of butadiene. Investigating a natural sample, we assign signals of two trans-1,3-butadiene isotopologues that contain a single (13)C isotope and quantify the fragment abundance for the (13)CH3 loss channel for each isotopologue.