Infrared spectrum of the silicon hydride cation SiH7 PLU

Yibin Cao, Jong-Ho Choi, Bernd Michael Haas, Matthew S. Johnson, Mitchio Okumura

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Silanium ions are an important class of hypervalent molecules, and the determination of their structure will yield insights into the nature of nonclassical bonding and provide a contrast to the bonding in carbonium ions. We report the infrared spectrum of the mass-selected silicon hydride cluster ion 28SiH7 +, detected by vibrational predissociation spectroscopy. Silanium ions were formed in a pulsed high pressure glow discharge and cooled by the subsequent supersonic expansion. Photodissociation spectra were obtained using a tandem time-of-flight mass spectrometer: SiH7 + ions were mass-selected and excited by a tunable infrared laser. The resulting photofragments were detected using a reflectron as a mass analyzer. We observed a vibrational band at 3865 cm-1, which was the only one observed from 3500 cm-1 to 4200 cm-1. This result suggests that the molecule might form a symmetric complex with the structure H 2·SiH3 +·H2, in contrast to the species CH 7 +, which has the structure CH5 +·H2.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
Place of PublicationBellingham, WA, United States
PublisherPubl by Int Soc for Optical Engineering
Number of pages6
ISBN (Print)0819410853
Publication statusPublished - 1993 Dec 1
Externally publishedYes


ASJC Scopus subject areas

  • Electrical and Electronic Engineering

Cite this

Cao, Y., Choi, J-H., Haas, B. M., Johnson, M. S., & Okumura, M. (1993). Infrared spectrum of the silicon hydride cation SiH7 PLU In Proceedings of SPIE - The International Society for Optical Engineering (Vol. 1858, pp. 326-331). Bellingham, WA, United States: Publ by Int Soc for Optical Engineering.