Maximum quantum efficiency of molecular lasers utilizing electron transitions and vibrational depopulation in the excited state

An investigation is made of the vibrational distribution of molecules in an electronically excited state subject to an allowance for the effects of the pumping, vibrational relaxation, electron quenching, and conversion to other states. Expressions for the quantum efficiency of the spontaneous luminescence and for the maximum quantum efficiency of the transformation of the pump radiation into laser radiation are derived and analyzed. The results are applied to an I₂(D'–A') laser.