Precise measurement and assignment of CW laser emission lines from optically pumped Na2 and Li2 molecules

The paper reports the precise wavelength measurement (0.01 A or 0.03 per cm) of CW laser emission lines from Li2 and Na2 molecules, optically pumped by a single frequency argon laser. All 22 lines from Li2 have been assigned unambiguously. The existence of pure Raman laser lines (nonresonant pumping and gain without population inversion) has been observed for the first time in these systems. Among the 49 lines from Na2, 13 could not be assigned, which suggests the possibility of other pumping mechanisms: collision induced transitions or two-step excitation to a higher electronic state.