Absolute measurements of state-to-state rotational energy transfer between CO and H2 at interstellar temperatures

TL;DR

This study provides precise experimental and theoretical data on rotational energy transfer rates between CO and H2 at interstellar temperatures, crucial for understanding molecular processes in space.

Contribution

It offers the first detailed experimental measurements that validate quantum scattering calculations for CO-H2 collisions at very low temperatures.

Findings

Excellent agreement between experiments and theory.

Validated quantum scattering calculations for interstellar conditions.

Provides essential data for astrophysical modeling.

Abstract

Experimental measurements and theoretical calculations of state-to-state rate coefficients for rotational energy transfer of CO in collision with H$_2$ are reported at the very low temperatures prevailing in dense interstellar clouds (5 - 20 K). Detailed agreement between quantum state-selected experiments performed in cold supersonic flows using time-resolved infrared - vacuum-ultraviolet double resonance spectroscopy and close-coupling quantum scattering calculations confirms the validity of the calculations for collisions between the two most abundant molecules in the interstellar medium.