Interestingly, there are also weak, continuous photoelectron distributions in the range 1.0–2.0 eV eKE, most noticeably in the 320 nm photoelectron spectrum. We attribute these to multiphoton processes or loss of CO2, followed by autodetachment from the decarboxylated motor anion which is expected to have a lower binding energy. We have identified CO2 loss as a competing decay channel in protein chromophore anions containing COO– using MS-MS measurements.56