Germanium Dicarbide: Evidence for a T-Shaped Ground State Structure
Oliver Zingsheim1, Marie-Aline Martin-Drumel2,3, Sven Thorwirth1
1I. Physikalisches Institut, Universität zu Köln , Zülpicher Straße 77, 50937 Köln, Germany.
The Journal of Physical Chemistry Letters
|July 26, 2017
Summary
Germanium dicarbide (GeC2) has a T-shaped structure, not L-shaped as previously predicted. Precise measurements confirm this molecular geometry and bond length.
Area of Science:
- Quantum Chemistry
- Molecular Spectroscopy
- Inorganic Chemistry
Background:
- The equilibrium structure of germanium dicarbide (GeC2) has been debated since the 1950s.
- Quantum calculations suggested an L-shaped geometry, but T-shaped or linear structures remained possibilities due to a flat potential energy surface.
Purpose of the Study:
- To experimentally determine the definitive equilibrium structure of germanium dicarbide (GeC2).
- To resolve the long-standing ambiguity regarding the molecular geometry of GeC2.
Main Methods:
- High-sensitivity microwave and millimeter-wave rotational spectroscopy were employed.
- Analysis of the rotational spectra of 14 isotopologues of GeC2 was performed.
Main Results:
- The study unambiguously established that GeC2 adopts a vibrationally averaged T-shaped structure in its ground state.
- A precise r0 structure was derived, with a Ge-C bond length of 1.952(1) Å and an apex angle of 38.7(2)°.
Conclusions:
- The experimental evidence refutes the previously favored L-shaped geometry for GeC2.
- The T-shaped structure provides a precise understanding of GeC2's molecular configuration and bonding.
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