Sobolev LVG Analysis of Prebiotic Molecule Formamide (NH2CHO) Found in the ISM

摘要

Using known values of rotational and centrifugal distortion constants in conjunction with electric dipole moment of NH2CHO, we have calculated energies of rotational levels in the ground vibrational state, and the probabilities for radiative transitions between the levels. The radiative transition probabilities in conjunction with the scaled values of collisional rate coefficients are used in the Sobolev LVG analysis of NH2CHO. There are some strong lines. For ortho-NH2CHO, we have found one transition 1(10)-1(11) showing anomalous absorption and five transitions 6(15)-5(14), 7(17)-6(16), 7(16)-6(15), 8(18)-7(17), 8(17)-7(16) showing emission feature. For para-NH2CHO, six emission transitions 5(05)-4(04), 6(06)-5(05), 7(07)-6(06), 8(08)-7(07), 9(09)-8(08), 10(0.10)-9(09) are found. Out of these 12 transitions, three transitions, 1(10)-1(11), 5(05)-4(04), and 8(08)-7(07), are already found in the ISM. Other relatively weaker lines are also found in the ISM. In addition to the observed lines, 9 transitions may play important role in the identification of NH2CHO in a cosmic object.