Knowledge Bank

The electronic emission spectrum of YH and YD has been investigated in the 690 nm to 3 $\mu m$ spectral region using a Fourier transform spectrometer. The YH and YD bands were excited in an yttrium hollow cathode lamp operated with neon gas and a trace of $H2$ of $D2$ The observed bands have been classified into three different electronic transitions; $C\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma +-X\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma +, d0\mathrm{<mrow\; data-mjx-texclass="ORD">+</mrow>}(\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Sigma )-X\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma +$ and $C3\Phi -a3\Delta$. The $d0\mathrm{<mrow\; data-mjx-texclass="ORD">+</mrow>}(\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Sigma )-X\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma +$ transition of YD could not be identified due to its very weak intensity. The rotational analysis of several bands of the $C\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma +-X\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma -$ transition (up to $v\prime \prime =3$ for YH and $v\prime \prime =2$ for YD) provides improved equilibrium vibrational and rotational constants for the ground state of YH and YD. The excited $C\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Sigma +$ state is involved in several perturbations.