Einstein A-coefficients for C3H2 and C2H4O

Cyclopropenylidene C_3_H_2_ and ethylene oxide C_2_H_4_O molecules are of astronomical importance as their observed lines, distributed throughout the observable microwave region, have a number of pairs having nearly equal frequencies, but different excitation energies and/or belonging to two different species of the molecule. Hence, these molecules may play important role in detecting physical conditions in cosmic objects.

Therefore, in order to calculate intensities of the lines, we have investigated transfer of radiation through a cosmic object containing the molecule at a kinetic temperature of 10K. Our results show that some lines of the molecule may be found in absorption against the cosmic 2.7K background.