Fourier transform microwave spectroscopy of SC13C2 and SC12C13C: establishing an accurate structure of SCC2 (~X2A1)

Abstract

Pure rotational spectra of Sc$^{13}$C$_{2}$ and Sc$^{12}$C$^{13}$C (\~{X}$^{2}$A$_{1}$) have been obtained using Fourier Transform Microwave methods. These molecules were created from scandium vapor in combination with $^{13}$CH$_{4}$ and/or $^{12}$CH$_{4}$, diluted in argon, using a Discharge Assisted Laser Ablation Source (DALAS). Transitions in the frequency range of 14-30 GHz were observed for both species including hyperfine splitting due to the nuclear spin of Sc ($I$ = 7/2) and $^{13}$C ($I$ = 1/2). Rotational, spin-rotational, and hyperfine constants have been determined for Sc$^{13}$C$_{2}$ and Sc$^{12}$C$^{13}$C, as well as a refined structure for ScC$_{2}$. In agreement with theoretical calculations and previous Sc$^{12}$C$_{2}$ results, these data confirm a cyclic (or T-shaped) structure for this molecule.

Scandium carbides have been shown to form endohedral-doped fullerenes, which have unique electrical and magnetic properties due to electron transfer between the metal and the carbon-cage. Spectroscopy of ScC$_{2}$ provides data on model systems for comparison with theory.