Knowledge Bank

High-resolusion infrared spectra of the weakly bound N$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$O-CO$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$ complex are studied using a tunable diode laser to probe a pulsed supersonic slit jet. The previously known N$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$O-CO$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$ dimer band in the region of the $\nu 3$ CO$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$ asymmetric strtch ($\sim$ $2350$ cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$) is remeasured and analyzed in improved detail and two new bands in the regions of the N$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$O $\nu 1$ ($\sim$ $2230$ cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$) and $\nu 3$ ($\sim$ $1280$ cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$) stretching fundamentals are observed and assigned to N$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$O-CO$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$. The ground state rotational constants for all three bands are $A=0.29498$ cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$, $B=0.05801$ cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$ and $C=0.04837$ cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$. We also observe another band with c-type rotational structure at about $2251.5$ cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$ which is assigned as a combination of the intramolecular N$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$O $\nu 1$ stretching vibration and the intermolecular out-of-plane torsional vibration. The resulting torsional frequency for the N$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$O-CO$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$ dimer is about $25.7$ cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$.