Photolysis of Disilane at 193 nm

The primary photochemical process of Si2H6 at 193 nm has been studied by us ing time-resolved mass spectrometry and laser-induced fluorescence (LIF) te chniques. Si Hr was confirmed as a primary photoproduct, but no signal due to SiH3, Si2H3, Si2H4 and Si2H5 in 193 nm photolysis has been detected. SiH 2 was observed in a pump-and-probe experiment by the LIF method, which rapi dly reacts with the Si2H6 parent molecule to form Si3H8. The quantum yield of Si3H8 produced in the reaction of SiH2 + Si2H6 was estimated to be 0.13 +/- 0.02 by using electron impact mass spectrometry. It was concluded that SiH2 produced by the photolysis exclusively reacted with Si2H6 and thus the quantum yield of SiH2 was equal to that of Si3H8, i.e., 0.13. The quantum yield of H atom was estimated to be 0.09 +/- 0.01 by using vacuum ultraviol et (VUV) LIF. On the basis of the existing data and present results, it was suggested that the H? molecule production channels are dominant in 193 nm photolysis of Si2H6.