Pulsed-laser photochemistry of pentanal at 355 nm

Pure pentanal is irradiated with a frequency tripled Nd-YAG laser in the intensity interval 0.1-1 MW. cm −2 . Alpha-dione and α-ketol are formed selectively with quantum yields of 5.5 and 38%, respectively. As only the S 1 state of the pentanal is excited, the results obtained are explicable as a dynamic effect in connection with the order of the reactions.