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…

We report on photoassociation spectroscopy probing the ${c}^{3}{\mathrm{\ensuremath{\Sigma}}}_{1}^{+}$ potential of bialkali NaCs molecule, identifying 11 vibrational lines between ${v}^{\ensuremath{'}}=0$ and ${v}^{\ensuremath{'}}=25$ excited fitting their rotational hyperfine structure. The observed are assigned by to an effective Hamiltonian model excited-state structure with constants as free parameters. discuss unexpected broadening select its possible link strong spin-orbit coupling nearby ${b}^{3}{\mathrm{\ensuremath{\Pi}}}_{1}$ ${B}^{1}{\mathrm{\ensuremath{\Pi}}}_{1}$ manifolds. Finally, we use ${v}^{\ensuremath{'}}=22$ line intermediate state for two-photon transfer weakly bound Feshbach molecules rovibrational ground ${X}^{1}{\mathrm{\ensuremath{\Sigma}}}^{+}$ manifold.