Identification of Rydberg States inNa2by Two-Step Polarization Labeling

The new excited ${}_{}{}^1{}_{}{}^{}\Delta _g^{}{}_{}{}^{}$ states and five new excited ${}_{}{}^1{}_{}{}^{}\Pi _g^{}{}_{}{}^{}$ states of ${\mathrm{Na}}_2$ have been identified with the use of the two-step polarization labeling technique. The electronic energies of these states form a molecular Rydberg series. By extrapolating the dissociation energies, vibrational constants, and rotational constants of these Rydberg states it is possible to obtain good estimates of the same quantities for the $X{}_{}{}^2{}_{}{}^{}\Sigma _g^{}{}_{}{}^{}$ ground state of ${\mathrm{Na}}_2^{+}$.