Propane consists of two CH3 radicals separated by CH2 a Calculation is here made on this systems of two rotors which interact each other at low temperature. Assuming the barrier height of CH3 rotation to be 517 cm-1, energy levels are figured up.
Considering the selection rule, spectral lines are calculated. The level splitting due to rotor-interaction is estimated for the assumed interaction-barrier-height b_??_50cm-1.