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


Single vibronic level dispersed fluorescence spectra of jet-cooled HGeCl and DGeCl have been recorded by laser excitation of selected bands of the à A″1–X̃ A′1 electronic transition. Twenty-six ground state vibrational levels of HGeCl and 42 of DGeCl were measured, assigned, and fitted to standard anharmonicity expressions, which allowed all the harmonic frequencies to be determined for both isotopomers. A normal coordinate least squares analysis obtained by fitting the harmonic frequencies yielded reliable values for five of the six force constants. The ground state effective rotational constants and force field data were combined to calculate average (rz) and approximate equilibrium (rze) structures, with rze(GeH)=1.586(1)Å, rze(GeCl)=2.171(2)Å, and the bond angle fixed at our CCSD(T)/aug-cc-pVTZ ab initio value of 93.9°. Comparisons show that the derived bond lengths are consistent with those of the appropriate diatomic molecules in their ground electronic states and the bond angle is similar to that of germylene (GeH2). A Franck-Condon simulation of the vibrational intensities in the 000 band emission spectrum of HGeCl using ab initio force field data shows good agreement with experiment, lending credence to the vibrational analysis of the observed spectra. I. INTRODUCTION

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This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Tackett, Brandon S., et. al., The Journal of chemical physics 124, no. 12 (2006) and may be found at https://doi.org/10.1063/1.2181142.

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The Journal of Chemical Physics