Correlation-driven ultrafast charge migration in pyrrole derivatives: the influence of the alkyl group

Pyrrole and its derivatives are essential components of many important organic molecules. By studying their response to ionization, we can gain insights into the photo-assisted reactions they participate in, as well as understand their overall photoresponse. In this study, we examine the effect of alkyl substitution in pyrrole derivatives on the ultrafast charge-migration dynamics initiated by inner-valence ionization. Using a multielectron wave-packet propagation approach, we investigate the correlation-driven charge redistribution in pyrrole (P), <i>N</i>-methylpyrrole (MP), and <i>N</i>-ethylpyrrole (EP). Additionally, we explore the stability of the π-conjugation structure involving the participation of the nitrogen's lone electron pair. Our findings reveal that as the length of the alkyl chain increases, significant charge migration and charge separation dynamics occur between the pyrrole and the alkyl group with only a small increase in the timescale.