Two-photon dissociation of NO near 275 nm investigated by velocity map imaging

The two-photon dissociation of NO at wavelengths near 275 nm has been investigated by velocity map imaging of the O(3P2) dissociation product. Two channels are seen, corresponding to formation of the co-product N atoms in their ground (4S) and excited (2D) states, and the relative yields and angular distributions measured. In their regions of maximum yield, the channel forming N(2D) produces unaligned products, whereas that producing N(4S) can be described by a β value of ca. 0.4. N(2D)/N(4S) ratios vary by a factor of 60 over a narrow range of excitation energies. The use of two-photon excitation of NO as a source of aligned atoms for reaction stereodynamics is discussed.