Related Experiment Video
Updated: Aug 22, 2026

Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F−
Published on: July 27, 2018
Half protons or doubly charged protons? The history of metastable ions
Herbert Budzikiewicz1, Ronald D Grigsby
1Institut für Organische Chemie der Universität zu Köln, Cologne, Germany. h.budzikiewicz@uni-koeln.de
Abstract:
The history of metastable ions is intertwined with that of ions formed by collision-induced dissociation (CID), and frequently the genesis of the two ion types cannot be strictly separated. Originally, metastable ions were considered a curiosity or even a nuisance, being responsible for "humps" in the base line of the recorded mass spectra. In their heyday metastable ions were recognized as having importance for establishing fragmentation sequences and for distinguishing between isomeric ion structures. Today, in many respects the utility of metastable ions has been superseded by a systematic application of CID techniques; yet the evaluation of their shape is still of importance for questions of reaction energies and ion thermochemistry.
Related Concept Videos
Ions and Ionic Charges
Nuclear Stability
To hold positively charged protons together in the...
Subatomic Particles
Electron Behavior
Electrons Orbit the Nucleus
Electrons are found in specific locations outside of the nucleus. The shell in which an electron resides indicates the general energy level of the electron: those closer to the nucleus have less energy,...
Electron Behavior
Atomic Structure
