Ionic fragmentation of SiH₄ following the K-shell excitation

Ionic fragmentation of SiH₄ has been studied in the vicinity of the Si: K-edge in the photon energy range 1800-1900eV. Ionic fragments observed at photon energies above the Si: Ls → σ* excitation are mostly atomic ions Si^q+ (q = 1-3) and H⁺. Ratios of the abundances for Si⁺, and Si²⁺ and Si³⁺ are roughly 4:4:1, and the abundance of H⁺ is much higher than the sum of the Si⁺, Si²⁺ and Si³⁺ abundances. The averaged kinetic energy release given to H⁺ is estimated to be about 12eV. This complete decomposition of SiH₄ with the ejection of energetic H⁺ is interpreted as Coulomb explosion of the multiply-charged (mainly +4 or +5) parent ion produced via the vacancy cascade (successive Auger and/or Coster-Kronig transitions).