High resolution photoassociation spectroscopy of the excited <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mi>c</mml:mi><mml:mn>3</mml:mn></mml:msup><mml:msubsup><mml:mi mathvariant="normal">Σ</mml:mi><mml:mrow><mml:mn>1</mml:mn></mml:mrow><mml:mo>+</mml:mo></mml:msubsup></mml:mrow></mml:math> potential of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mmultiscripts><mml:mi>Na</mml:mi><mml:mprescripts/><mml:none/><mml:mn>23</mml:mn></mml:mmultiscripts><mml:mmultiscripts><mml:mi>Cs</mml:mi><mml:mprescripts/><mml:none/><mml:mn>133</mml:mn></mml:mmultiscripts></mml:mrow></mml:math>
Lewis R. B. Picard, Jessie T. Zhang, William B. Cairncross, Kenneth Wang, Gabriel E. Patenotte, Annie J. Park, Yichao Yu, Lee R. Liu, Jonathan D. Hood, Rosario González‐Férez, Kang-Kuen Ni
Abstract
We report on photoassociation spectroscopy probing the ${c}^{3}{\mathrm{\ensuremath{\Sigma}}}_{1}^{+}$ potential of the bialkali NaCs molecule, identifying 11 vibrational lines between ${v}^{\ensuremath{'}}=0$ and ${v}^{\ensuremath{'}}=25$ of the excited ${c}^{3}{\mathrm{\ensuremath{\Sigma}}}_{1}^{+}$ potential and fitting their rotational and hyperfine structure. The observed lines are assigned by fitting to an effective Hamiltonian model of the excited-state structure with rotational and hyperfine constants as free parameters. We discuss unexpected broadening of select vibrational lines and its possible link to strong spin-orbit coupling of the ${c}^{3}{\mathrm{\ensuremath{\Sigma}}}_{1}^{+}$ potential with the nearby ${b}^{3}{\mathrm{\ensuremath{\Pi}}}_{1}$ and ${B}^{1}{\mathrm{\ensuremath{\Pi}}}_{1}$ manifolds. Finally, we report use of the ${v}^{\ensuremath{'}}=22$ line as an intermediate state for two-photon transfer of weakly bound Feshbach molecules to the rovibrational ground state of the ${X}^{1}{\mathrm{\ensuremath{\Sigma}}}^{+}$ manifold.