High‐Energy Long‐Lived Excited States in DNA Double Strands

Dark DNA light: “Dark” excited states of alternating GC double strands emit fluorescence at 4000 cm−1 higher energy (see spectrum) and with four orders of magnitude longer lifetime compared to the bright ππ* states. Such high-energy long-lived excited states are expected to play a key role in the DNA photoreactivity associated with the appearance of carcinogenic mutations.