The 7-azaindole (7-AzI) cluster anions and their H2O adducts were generated by electron attachment to the 7-AzI/7-AzI-H2O clusters, and their electronic properties studied with mass spectrometry and photoelectron spectroscopy. In the mass spectra of the 7-AzI cluster anions, (7-AzI)-n, monomer anions were missing due to negative electron affinity (EA), while clusters (n ≥ 2) have positive EA, and those having even n were more abundant than those at odd n. EA increased with cluster size from 0.88 eV at n = 2, and an even-odd alternation in the EA was seen. The even-odd alternation showed that the 7-AzI dimer acts as a unit for cluster formation. In the photoelectron spectrum of (7-AzI)-2 at 266 nm, the second peak was observed 2.4 eV above the first peak; this is attributed to the triplet state of the neutral (7-AzI)2. Depending on the detachment energy, a movable peak, with the detachment of 420-300 nm (2.9-4.1 eV), was additionally observed between the first and the second peaks; this was thought to be caused by a delayed photoemission via an electronic excited state of the (7-AzI)-2 anion.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics