Photolysis of dimethylnitrosamine in the gas phase

Abstract Photodecomposition of dimethylnitrosamine in the gas phase ( ∼ 1 Torr) has been investigated following irradiation into the S 1 (nπ*) ← S 0 (363.5 nm) and S 2 (ππ*) ← S 0 (248.1 nm) transitions at room temperature. With a quantum yield of unity, excitation into the S 1 state yields the fragments (CH 3 ) 2 N⋅ and NO which then recombine leaving no photoproducts. The addition of O 2 results in only one photoproduct, (CH 3 ) 2 NNO 2 . Irradiating into the S 2 state, the products CH 2 NCH 3 , (CH 2 NCH 3 ) 3 , CH 2 NOH, N 2 O, NO, H 2 , and N 2 were identified by capillary gas chromatography mass spectrometry. In the presence of N 2 as a buffer gas the photoproducts are only CH 2 NCH 3 , (CH 2 NCH 3 ) 3 , N 2 O, and H 2 . For both excitation conditions a mechanism is proposed involving cleavage of the N, N‐bond as the main primary photolytic process.