High resolution infrared spectroscopy and semi-experimental structures of Si2C3 and Ge2C3

Molecular species of group 14 elements e.g. carbon, silicon, and germanium are well suited to study cumulenic bond properties and to compare experimental results with high level quantum chemical calculations. In our recent investigation of SiC$_3$Si and GeC$_3$Ge, a high resolution laser spectrometer has been used to record rotationally resolved spectra of selected isotopologues at 5 $\mu$m.\\ We derived semi-empirical values for Si-C and Ge-C bond distances based on spectroscopic data and corresponding zero-point vibrational corrections calculated at the CCSD(T)/cc-pVXZ level of theory (with X = T and Q). Comparison of semi-empirical structural parameters with those from quantum chemical calculations reveals very good agreement for both molecules. Relativistic effects are found negligible for SiC$_3$Si and small for GeC$_3$Ge.Ope

Gas-Phase Spectroscopic Detection and Structural Elucidation of Carbon-Rich Group 14 Binary Clusters: Linear GeC3Ge

Guided by high-level quantum-chemical calculations at the CCSD(T) level of theory, the first polyatomic germanium-carbon cluster, linear Ge2C3, has been observed at high spectral resolution in the gas phase through its remarkably complex fundamental antisymmetric C-C stretching mode ν3 located at 1932 cm(-1). The observation of a total of six isotopic species permits the derivation of a highly accurate value for the equilibrium Ge-C bond length. The present study suggests that many more Ge-C species might be detectable in the future using a combination of laser-ablation techniques for production and high-resolution infrared and/or microwave techniques for spectroscopic detection

Gas-Phase Spectroscopic Detection and Structural Elucidation of Carbon-Rich Group 14 Binary Clusters: Linear GeC₃Ge

Guided by high-level quantum-chemical calculations at the CCSD­(T) level of theory, the first polyatomic germanium–carbon cluster, linear Ge₂C₃, has been observed at high spectral resolution in the gas phase through its remarkably complex fundamental antisymmetric C–C stretching mode ν₃ located at 1932 cm^–1. The observation of a total of six isotopic species permits the derivation of a highly accurate value for the equilibrium Ge–C bond length. The present study suggests that many more Ge–C species might be detectable in the future using a combination of laser-ablation techniques for production and high-resolution infrared and/or microwave techniques for spectroscopic detection

High-Resolution Spectroscopy of C₃ around 3 μm

We report on the detection of the (10⁰1) ← (00⁰0) vibrational band of gas-phase C₃ and the two of its mono ¹³C substituted isotopologs in the infrared region around 3200 cm^–1. Additionally, the associated hot band (11¹1) ← (01¹0) has been assigned for the parent isotopolog. Spectra have been recorded using a supersonic jet spectrometer with a laser ablation source in combination with a continuous-wave optical parametric oscillator as radiation source. High-level quantum-chemical ab initio calculations have been performed and used to assist the assignment. A combined fit for the vibrational states of C₃ found in this study has been done together with previously reported high-resolution data to increase the accuracy of the molecular parameters, especially for the ground state. The vibrational energies are 3260.126, 3205.593, and 3224.751 cm^–1 for the (10⁰1) state of C₃, ¹²C¹³C¹²C, and ¹³C¹²C¹²C, respectively. The (11¹1) state of C₃ has been found to be at 3330.509 cm^–1