Quantitative photoexcitation study of SiH4 in vacuum ultraviolet

Abstract

The photoabsorption and fluorescence cross sections of SiH₄ were measured in the 106–160 nm region using synchrotron radiation as a light source. Two states with long vibrational progressions in the 106–123 nm region were observed and assigned to the 5s and 6s Rydberg series converging to the first ionization state (2t₂)⁻¹. The wavelength thresholds for producing fluorescences from the SiH ( A ²Δ→X ²Π) and Si (4s ¹P⁰→3P^{2 1}D₂) transitions were observed at 131.5 and 120.0 nm, respectively. The quantum yields for both fluorescence systems were measured. The photodissociation processes for producing the excited fragments of SiH* ( A ) and Si* are discussed.