Aminotetrazine–argon, the world's smallest ‘large gas-phase cluster’
Abstract
The photodissociation dynamics of the complexes aminotetrazine–Ar and aminotetrazine–Ar2 have been studied using supersonic jet spectroscopy. The lowest excited electronic state of aminotetrazine was found to have a much longer fluorescence lifetime (154 ns in the vibrationless level) than tetrazine (0.9 ns), and the photodissociation reaction could be followed for a much longer time than was the case with tetrazine. It was found that the photodissociation rate varied dramatically depending on the initially excited vibronic state. Excitation of the 16b2 level of aminotetrazine–Ar at Uo+ 446 cm–1 produced complete dissociation during the fluorescence lifetime, while excitation of the 6a1 level at Uo+ 606 cm–1 produced very little dissociation. Thus, this simple complex could store considerable excess energy for more than a microsecond without dissociating. The photodissociation rates of the complex aminotetrazine–Ar2 also depended strongly on the initially excited state. Moreover, the dissociation product branching ratio of aminotetrazine–Ar2 between the aminotetrazine–Ar and the free aminotetrazine photoproducts also varied greatly from state to state.