Anomalous absorption in 202-111 transition of methanimine

Abstract

The methanimine molecule is of great interest for astronomers and astrophysicists. It is considered as a prebiotic molecule as it is a potential precursor of Glycine, the simplest amino acid. The reaction of CH2NH with HCN in interstellar medium makes aminoacetonitrile (NH2CH2CN) which further reacts with H2O to make glycine (NH2CH2COOH). The amino-acids like Glycine are building blocks of proteins that are essential for life to occur. Earlier, we have calculated the radiative lifetimes and Einstein A-coefficients for transitions between 69 lowest rotational energy levels of methanimine. In the present study, we have obtained the anomalous absorption in 202 – 111 transition of methanimine at 33.705893 GHz. We have solved the statistical equilibrium equations coupled with the equations of radiative transfer. The brightness temperature is found to be minimum around the hydrogen molecular density of 104.5 cm−3 and it rises on both sides of this density.