Cover Picture: Exploring the Mechanism of IR-UV Double-Resonance for Quantitative Spectroscopy of Protonated Polypeptides and Proteins (Angew. Chem. Int. Ed. 23/2013)

Abstract

Determination of the 3D structures …︁ …︁ of large molecules challenges spectroscopy to perform better. In their Communication on page 6002 ff. O. V. Boyarkin et al. use IR–UV double-resonance cold-ion spectroscopy for conformational assignment of the electronic spectra of a protonated decapeptide and for measurements of absolute absorption cross-sections of vibrational transitions in this species. The limitations of the IR–UV double-resonance approach are illustrated by measuring the gas-phase IR spectrum of a cold, protonated intact protein.