High temperature, high density observation and modeling of the lithium 1 3Σu+ − 1 3Πg transition

Optical absorption of the Li2 1 3Σu+ − 1 3Πg transition, with a satellite maximum at 603.9 nm, at an estimated temperature of 2033 K and estimated lithium vapor density of 2.97 × 1018 cm−3 is reported. These are the first results from a new experimental device, the plasma spectroscopy cell. Fully quantum mechanical calculations of bound-free and free-free absorption cross sections for the transition are presented to confirm identification of the triplet transition and to establish the domination of free-free absorption.