Work

Testing the photostability of 1-Cyanonaphthalene-(H2O)1,2 complexes to predict their resistance to the interstellar radiation field

Year: 2026

Type: article

Abstract: The studies of spectroscopy, reactivity, and photochemistry of CN-substituted aromatic molecules have acquired particular relevance since their detection in TMC-1 in 2018. In this context, the REMPI spectroscopy of 1-cyanonaphthalene (1CNN) and its complexes with one (1CNN-W) and two (1CNN-W2) water molecules (W = H2O) was recorded and compared with theoretical calculations at the CAM-B3LYP/aug-cc-pVDZ level, validating the theoretical method and justifying its use in predicting some properties of the neutral and ionic species in their ground and excited electronic states. The adiabatic ionization potential (IPad) for 1CNN monomer was experimentally determined for the first time (8.431 eV) in good agreement with the theoretical value (8.417 eV). Ionization thresholds for 1CNN-W and 1CNN-W2 complexes and the water evaporation threshold in the cationic state of the latter complex were also determined experimentally and compared satisfactorily with theoretical results. Based on the available data, it is tentatively predicted that once 1CNN aggregates with ≥ 1 H2O molecules, these complexes will be ionized by Ly-α irradiation, but they will be stable in their cationic state.

Source: Journal of Molecular Spectroscopy

DOI: 10.1016/j.jms.2026.112078