Anomalous absorption in H2CN and CH2CN molecules

Structures of H2CN and CH2CN molecules are similar to that of H2CO molecule. The H2CO has shown anomalous absorption for its transition 1(11) - 1(10) at 4.8 GHz in a number of cool molecular clouds. Though the molecules H2CN and CH2CN have been identified in TMC-1 and Sgr B2 through some transitions in ortho as well as in para species, here we have investigated the condition under which transitions 1(11) - 1(10) and 2(12) - 2(11) of these molecules may show anomalous absorption. For the present investigation, we have calculated energy levels and radiative transition probabilities. However, we have used scaled values for collisional rate coefficients. We found that relative values of collisional rate coefficients can produce the required anomalous absorption in 1(11) - 1(10) and 2(12) - 2(11) transitions in the molecules.