IR emission from vibrationally excited molecules as a probe of chemistry in cold, dark interstellar clouds

Abstract

Molecule formation in interstellar clouds can leave molecules such as H2, CH+, |$\text {CH}^+_2$|⁠, CO, etc. in vibationally excited states. In general, molecules lose this excitation by emission of IR radiation. We discuss the possibility of detecting this emission in dark interstellar clouds and show that emission from vibrationally excited H2, |$\text {H}^+_3$| and CO should be detectable. Detection (or non-detection) of this radiation would provide important information on chemical reaction routes in dark interstellar clouds.