Chemical reaction jet spectroscopy, molecular structure, and the bending potential of the A 1A″ state of monofluorosilylene (HSiF).

The jet-cooled laser induced fluorescence excitation spectrum of the A 1A″–X 1A′ band system of HSiF has been observed with the chemical reaction jet technique. Vibrational analysis of the spectrum gave upper state fundamental vibrational frequencies of ν1=1547 cm-1, ν2=558 cm-1, and ν3=857 cm-1. Seven bands in the spectrum were recorded at high resolution and rotationally analyzed, providing excited state molecular constants. The upper state vibrational and rotational bending levels were fitted to a semirigid bender model to obtain the equilibrium geometry and the potential energy barrier to linearity. Due to correlations in the parameters, it was necessary to fix the bond angle at the ab initio value of 114.5°. The resulting fitted model yielded re(Si–F)=1.602 Å, re(Si–H)=1.548 Å with a potential energy barrier to linearity of 9130 cm-1. © 1995 American Institute of Physics. [ABSTRACT FROM AUTHOR]