A bimolecular mechanism for ketene photodissociation in the near ultraviolet

The photochemistry of ketene has been studied at 3130, 3340, and 3660 Å. Quantum yields for carbon monoxide, ethylene, ethane, and acetylene were measured versus pressure. As p→0 the carbon monoxide quantum yield approaches 2 at each of the three wavelengths. Ethane and acetylene exhibit linear Stern-Volmer plots at 3130 and 3340 Å. However, at 3660 Å no acetylene was detected and ethane is formed in trace amounts. The above measurements are interpreted in terms of a mechanism which involves adduct formation between the ¹A₁, and ¹A ₂(¹A″) electronic states of ketene.