Rotational spectrum of silyl chloride: hyperfine structure and equilibrium geometry

Abstract

The Lamb-dip technique was employed to record the rotational spectra of two isotopic species of silyl chloride, namely ²⁸SiH₃Cl and ²⁹SiH₃Cl, in order to investigate their hyperfine structure. High-accuracy quantum-chemical computations were employed to predict the hyperfine parameters involved and to support the experimental investigation. Analysis of the experimental spectra led to an improvement in the accuracy of the known spectroscopic constants as well as allowed us to determine additional spectroscopic parameters for the first time. Furthermore, the equilibrium structure of silyl chloride was reinvestigated using both theoretical and experimental data. The best theoretical and semi-experimental geometries were found to agree within their stated accuracy, leading to the following recommended structure: r(Cl–Si) = 2.046(1)Å, r(Si–H) = 1.469(1)Å, and ∠ClSiH = 108.43(1)^○.

Keywords:

• silyl chloride
• Lamb-dip technique
• hyperfine parameters
• equilibrium structure
• quantum-chemical calculations

Acknowledgements

This work has been supported by ‘PRIN 2009’ funds and by the University of Bologna (RFO funds) as well as in Mainz by the Deutsche Forschungsgemeinschaft (GA 370/5-1) and the Fonds der Chemischen Industrie.

Notes

Note

1. A sign convention for spin–rotation constants opposite to that originally used by Flygare 55 is adopted.