Experimental observation of quantum interferences in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mtext>CO</mml:mtext> <mml:mtext>−</mml:mtext> <mml:msub> <mml:mi mathvariant="normal">H</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:

Using time-resolved infrared--vacuum-ultraviolet double-resonance spectroscopy, experimental room-temperature measurements of state-to-state rate coefficients for rotational energy transfer within the $X{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\ensuremath{\Sigma}}}^{+}(v=2)$ vibrational state of CO due to ${\mathrm{H}}_{2}$ collisions have been compared to accurate four-dimensional close-coupling quantum calculations. Theoretically predicted quantum interferences in the ${\text{CO-H}}_{2}$ collisional system are experimentally observed at room temperature, and excellent agreement between theory and experiment is observed. These results provide a valuable benchmark for validating the anisotropic part of the potential energy surface, thereby supporting the theoretical modeling of CO emission in warm astrophysical environments such as photodissociation regions.