Determination of the spectral dependences of the absolute quantum yields of XeF(B, C, D) excimers in photolysis of XeF2

Photolysis of XeF₂ accompanied by the formation of excited XeF(B, C, D) molecules is of interest since this reaction is used in optically pumped excimer lasers. The present paper reports an investigation of the photolysis of gaseous XeF₂ in the 220–108 nm spectral range. It was established that the maximum quantum yields of XeF(B) and XeF(C) in the 140–180 nm range are 30 ±9 and 3.5 ± 1%, respectively (λ_max≈165 nm). The quantum yield of XeF(D) in this range does not exceed 1.5%. A mechanism for decay of excited XeF₂ molecules is discussed. It is found that several electronic transitions make a contribution to the XeF₂ absorption band which has a maximum at 158 nm. It is postulated that a transition to the ¹Π_g or ³Π_u states in this band results in the formation of XeF(D), a transition to the ¹Π_u state results in the formation of XeF(X or A), and transitions to the ¹Σ_u⁺ and ³Σ_u⁺ states result in the formation of XeF(B) and XeF(C), respectively.