The 61πμ state of Na2 molecule

Excitation spectra of sodium dimer were analysed within the range 34200-36400 cm(-1). The experiment was done using polarisation labelling spectroscopy technique. In the spectral region under investigation we found several vibrational progressions belonging to a single band system having the ground state of Na-2 as the, lower state. The upper state was of (1)Pi(u) symmetry as indicated by the presence of Q lines in the spectrum and basing on theoretical calculations it was identified as the 6(1)Pi(u) (3s+4f) state. The Dunham coefficients and potential curve characterising this state were deduced from the observed spectra.