Competing πσ* States in the Photodissociation of Adenine

Despite the extensive investigations thus far, there is still debate regarding the role of the repulsive pi sigma* state in the photochemistry of adenine. We present evidence that suggests that H-atom elimination via both the azole group (N-9) and the often overlooked amino group (N-6) occurs following excitation at 200 nm. In contrast, excitation at 266 nm supports the view that the role of the pi sigma* states is minimal.