Complex photodissociation dynamics of the weakly bound covalent NO dimer
In collaboration with several experimental and theoretical groups, complex photodissociation dynamics of the NO dimer were uncovered. (NO)2 is unstable at room temperature, but exists in cold atmospheres and on cold surfaces, where it behaves differently than the NO radical. It strongly absorbs UV radiation and falls apart.
The bonding in the dimer is intermediate between the covalent and van der Waals, as evidenced by binding energy and the NN bondlength. It derived from distributing two electrons in four nearly degenerate orbitals made of the singly occupied π* orbitals of the NO monomer.
Femtosecond experiments by Albert Stolow revealed different time scales for the (NO)2* dissapearance and NO(A) appearance.