Precise measurement and assignment of CW laser emission lines from optically pumped Na2and Li2molecules

We report the precise wavelength measurement (0.01 Å or 0.03 cm^-1) of CW laser emission lines from Li2and Na2molecules, optically pumped by a single frequency argon laser. All 22 lines from Li2have been assigned unambiguously. We observed, for the first time in these systems, the existence of pure Raman laser lines (nonresonant pumping and gain without population inversion). 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.