UV Photolysis of N₂O Isotopomers: Isotopic Fractionations and Product Rotational Quantum State Distributions

The time-dependent quantum wave packet method is used to study the dynamics of the pho-todissociation processes for the isotopomers ¹⁴N¹⁴N¹⁶O, ¹⁴N¹⁵N¹⁶O, ¹⁵N¹⁵N¹⁶O, ¹⁵N¹⁵N¹⁶O, ¹⁴N¹⁴N¹⁷O, and ¹⁴N¹⁴N¹⁸O. In general, the computed isotopic fractionation factors derived from the absorption cross sections of five heavy isotopomers are in good agreement with the experimental results. Relative to the ¹⁴N¹⁴N¹⁶O isotopomer, the N₂ rotational state distributions for the isotopically nitrogen substituted N₂O are found to be entirely shifted to higher rotational states. Similar to its isotopic fractionation factors, the N₂ rotational state distributions for the asymmetric isotopomers ¹⁴N¹⁵N¹⁶O and 15N¹⁴N¹⁶O are found to be observably different.