MULTICHANNEL QUANTUM DEFECT THEORY APPLIED TO HIGH-LYING RYDBERG STATES IN $He_{2}$

Abstract

Multichannel quantum defect theory (MQDT) based methods have been used to extend the analysis of emission spectra of $He_{2}$. High-lying Rydberg levels with $(1\sigma_{g}{^{2}}1\sigma)np\sigma^{e}$ and $(1\sigma_{g}{^{2}}1\sigma_{u})\Pi p\Pi$ ancestry with $n^{*}$ -values up to $\sim 18$ have been analyzed and the MQDT parameters evaluated. Vibrational and rotational $(N \leq \sim 20)$ effects are included. These data emphasize the breakdown of one electron models for molecular Rydberg states near their ionizations limits.