Near-UV photodissociation of phosphopeptide cation-radicals

- We report near-UV photodissociation spectra of phosphopeptide ions generated by ETD.
- The peptide cation-radicals have chromophores absorbing light at 355 nm.
- Excited state calculations identify the chromophores and explain the spectra.
- Near-UV photodissociation spectra differ from collision induced dissociation.