The photodissociation of cis-(NO)2 in N2 and Ar matrices under 266 nm pulsed laser irradiation is reported- Results show the electronically excited o(1D) atom may be formed in the primary photolysis step. In the N2 matrix, the highly active o(1D) atoms could either react with N2 lattice molecules forming N2O or recombine with nearby N2O forming cis-(NO)2 and trans-(NO)2. However, in the Ar matrix the nascent state o(1D) atom, due to the lack of reactant, quenches to O(3P) as moving through the lattice site and the yield of N2O is less than that in N2 matrix.
