Infrared spectroscopy of the siliconium ion, SiH+5

Abstract
The infrared spectrum for the H–H stretching mode of the siliconium ion SiH+5 in the frequency range of 3650–3740 cm−1 is presented. The observed vibration–rotation transitions were fitted with the A‐type rotational transitions of an asymmetric top using the Watson S‐type asymmetric top rotational Hamiltonian. The results suggested that the siliconium ion SiH+5 can be described as a complex between SiH+3 and a freely internally rotating H2 groups, with a highly localized three‐center two‐electron bond.