Ultraviolet photodissociation spectroscopy of cold, isolated adenine complexes with a potassium cation

- We obtain the UV photodissociation spectrum of K+ adenine stored in a cold ion trap.
- K+ adenine exists as a single isomer where K+ ion binds to 7H-adenine.
- K+ ion plays a catalytic role in the tautomerization of 9H-adenine.
- The energy barrier for tautomerization varies depending on the binding site of K+ ion to 9H-adenine.