Quenching of interstellar carbenes: Interaction of C 3 H 2 with He and H 2

Synopsis C3H2 molecules are ubiquitous in the Galaxy and present important challenges in their chemistry, whether cyclic or linear, and possibly substituted with D. Obtaining theoretical rotational quenching rates by collisions with He and H2 as projectiles is of great importance in order to get quantitative abundance estimates. It is all the more challenging that many rotational lines are excited during the collision, resulting in computationnally very heavy quantum dynamics. The quality of various approximations will be discussed, as well as the quenching rates for astrophysical applications.