Figure 1
From: Revealing Deactivation Pathways Hidden in Time-Resolved Photoelectron Spectra

The investigated structures.
(a,b) are the syn- and anti-rotamers of enol cytosine, (c) is keto-cytosine and (d) imino-cytosine. The terms syn and anti refer to the rotamers of the OH-group with respect to the -NH2 group. Hydrogens attached to carbons were omitted for clarity.