Production of N2 O from collisional quenching of electronically excited OH…A 2 R‡ † by N2 was investigated in order to establish the importance of this process in the atmospheric budget of N2 O. The experimental approach, sequential pulsed laser production and excitation of OH combined with N2 O detection by tunable diode laser absorption spectroscopy, minimizes interferences from potential artifact sources of N2 O. The quantum yield for production of N2 O is found to be less than 1 × 10-4 , i.e., more than 100 times lower than the threshold for atmospheric importance. Ó 2001