Multiphoton Ionization Spectra for Fragment Ions of SiH₄

UV MPI spectra for fragment ions of SiH₄ have been first observed using dye laser as a light source and TOF mass spectrometer for ion detection. No SiH₄⁺ can be found. SiH₂⁺ and SiH₃⁺ are main products, and SiH⁺ is scarce. Comparing to the results of synchrotron radiation^7,13, the ratio of SiH₂⁺/ SiH₃⁺ is in agreement, however, Si⁺ is much stronger. In the region of 358-367nm the fragment ion spectra have similar figures. In the region of 377-393nm some additional bands appear in the Si⁺ spectrum. Most of those extra Si⁺ are probably produced from the succeeding dissociation of SiH_n⁺.