OPTICAL-OPTICAL DOUBLE-RESONANCE EXCITATION SPECTRA OF THE (6d)¹\Pi_g, (7d)¹\Pi_g HIGH-LYING RYDBERG STATES IN Na₂

Two ¹\Pi_g states of Na₂ for v≤13 have been observed by using optical-optical double resonance (OODR) fluorescence excitation spectroscopy. The intermediate levels in B¹\Pi_u state are identified by the numerical calculations with the molec-ular constants for B¹\Pi_u←X¹\Sigma_g⁺ transitions and confirmed by the complemen-tary A¹\Sigma_g⁺←X¹\Sigma_g⁺ polarization spectra. Absolute vibrational numberings of the (6d)¹\Pi_g and (7d)¹\Pi_g states are determined by comparing the experimental OODR excitation intensities with the simulated Franck-Condon factors. The Dnnham coef-ficients and the Rydberg-Klein-Rees (RKR) potential energy curves of the (6d)¹\Pi_g, (7d)¹\Pi_g states are reported.