RYDBREG STATES OF ${Li_{2}}$ AND MOLECULAR CONSTANTS OF ${Li_{2}}^{+}$

Abstract

Thirty-one new excited gerade states of $^{7}Li_{2}$ have been characterized by means of pulsed optical-optical double resonance spectroscopy. Twenty-nine of these have been identified as the lowest members of three Rydberg series: $3-15d\pi^{1}\Pi_{g}, 3-10d\sigma^{1}{\Sigma^{+}}_{g}$, and $3-10s\sigma^{1}{\Sigma_{g}}^{+}$, A fit of a Rydberg formula to the $^{1}{\Pi^{-}}_{g}$ term energies yield a value of $41496\pm 4 cm^{-1}$ for the ionization potential of $Li_{2}$. Extrapolations of the vibrational frequencies, rotational constants, and dissociation energies of these states give estimates for the corresponding quantities for the ground state of ${Li_{2}}^{+}$ which are in good agreement with those obtained by ab initio $calculations^{1}$.