Electron Loss and Dissociation Pathways of a Complex Dicarboxylate Dianion: EDTA.

Photoelectron imaging of the doubly deprotonated ethylenediaminetetraacetic acid dianion (EDTA) at variable wavelengths indicates two electron loss pathways: direct detachment and thermionic emission from monoanions. The structure of EDTA is also investigated by electronic structure calculations, which indicate that EDTA has two intramolecular hydrogen bonds linking a carboxylate and carboxylic acid group at either end of the molecular backbone. The direct detachment feature in the photoelectron spectrum is very broad and provides evidence for a dissociative photodetachment, where decarboxylation occurs rapidly after electron loss.

Photoelectron spectroscopy of the deprotonated tryptophan anion: the contribution of deprotomers to its photodetachment channels.

Photoelectron spectroscopy and electronic structure calculations are used to investigate the electronic structure of the deprotonated anionic form of the aromatic amino acid tryptophan, and its chromophore, indole. The photoelectron spectra of tryptophan, recorded at different wavelengths across the UV, consist of two direct detachment channels and thermionic emission, whereas the = 4.66 eV spectrum of indole consists of two direct detachment features.

Photodissociation of permanganate (MnO) produces the manganese dioxide anion (MnO) in an excited triplet state.

Photoelectron imaging, electron action spectroscopy and electronic structure calculations are used to probe the structure and dynamics of MnO. Following excitation to the first bright absorption band of MnO (1T), photodetachment, ground state electron loss, and photodissociation, to produce MnO, are both observed to occur simultaneously. MnO is produced in an excited electronic state, identified as a triplet state, which indicates that the dissociation proceeds on singlet potential energy surfaces spin conservation.

Unraveling the decarboxylation dynamics of the fluorescein dianion with fragment action spectroscopy.

The decarboxylation dynamics of the doubly deprotonated fluorescein dianion, Fl2-, are investigated by recording fragment action spectra for the anion, Fl-, and its decarboxylated analog, Fl-CO2-, using a new reflectron secondary mass spectrometer. The formation of the anion, Fl-, is directly investigated by photoelectron imaging. The Fl- and Fl-CO2- action spectra indicate that, for λ < 400 nm, one-photon dissociative photodetachment, i.