Structural and spectroscopic trends in the ground states of the monohalosilylenes: Emission spectroscopy of jet-cooled HSiI and DSiI

Abstract

Single vibronic level emission spectra of jet-cooled HSiI and DSiI have been recorded by laser excitation of selected bands of the Ã1A″–X̃1A′ electronic transition. The data have been used to derive the ground state harmonic frequencies and anharmonicities for both isotopomers. A normal coordinate analysis of the harmonic frequencies yielded reliable values for five of the six force constants. Using previously determined ground state rotational constants and the force field data, average (rz) and approximate equilibrium (rez) structures were calculated, with rez(SiH)=1.5151(2) Å, rez(SiI)=2.4610(1) Å, and θez(HSiI)=92.5(1)°. A comparison of trends in the structural parameters and vibrational frequencies of the monohalosilylenes shows that the bond angle increases significantly and the Si–H bond length decreases slightly with heavier halogen substitution. These trends have been rationalized based on the inductive effect and the electronegativity of the halogen substituent.

The ground state energy levels and molecular structure of jet-cooled HGeCl and DGeCl from single vibronic level emission spectroscopy

“…As expected, deuteration substantially decreases 1 Finally, we can compare the structural parameters of HGeCl to those of similar molecules. 10 The Ge-Cl bond length of 2.171 Å is not in particularly good agreement with the experimental 23 GeCl value of 2.144 Å, but the latter was calculated based on a previously published 41 value of ␣ e , which may be in error.…”

New ab initio potential energy surfaces for both the ground (X̃1A′) and excited (Ã1A″) electronic states of HSiCl and the absorption and emission spectra of HSiCl/DSiCl

“…Monochlorosilylene (HSiCl) is known as a member of the silylene family of reactive intermediates and plays an important role in semiconductor growth processes for the production of silicon thin films 1, 2. In the last decades, the structures, chemical kinetics, energetics, and other physical properties of these transient molecules have been extensively studied 1–9. However, since these intermediates are typically short‐lived and highly reactive, they are difficult to be monitored.…”

Ab initio potential energy surfaces for both the ground (X̃ A1′) and excited (Ã A1″) electronic states of HGeCl and the absorption and emission spectra of HGeCl/DGeCl

“…[1][2][3][4][5][6][7][8][9] However, the detailed mechanism of such processes is still not fully understood due partly to the lack of definitive spectroscopic signatures. [1][2][3][4][5][6][7][8][9] However, the detailed mechanism of such processes is still not fully understood due partly to the lack of definitive spectroscopic signatures.…”