Knowledge Bank

Fluorescence excitation spectra of gaseous TaCH and TaCD have been recorded following reaction of laser-ablated tantalum with $CH4$ or $CD4$ under jet-cooled molecular beam conditions. A total of 27 bands of TaCH and 18 of TaCD were observed in the visible region. High resolution spectra reveal the $X~0+$ ground state to have the substitution structure $r0(Ta-C)=1.7714$ {\AA} and $r0(C-H)=1.080$ {\AA}. Since the $X~0+$ state has no orbital or spin angular momentum, we observe only quadrupole splitting due to the $\mathrm{<mrow\; data-mjx-texclass="ORD">181</mrow>}Ta$ nucleus $(I=7/2)$. Resolved fluorescence studies have given the TaCH ground state vibrational frequencies $\nu 2(bend)=640cm-1$ and $\nu 3(Ta-Cstretch)=960cm-1$. Analysis is currently underway on an $\Omega =0+$ state at $16391.9cm-1$ and an $\Omega =1$ state at $16376.0cm-1$. Through mixing with the $\Omega =1$ state, the upper $\Omega =0+$ state has acquired some magnetic hyperfine character.