Rydberg states and ionization potential of calcium monofluoride

Abstract

61 vibronic states of CaF in the region 41 930--45 905 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ are observed by optical-optical double resonance, rovibronically assigned, and shown to belong to 37 Rydberg electronic states. These states are organized into six core-penetrating (l\ensuremath{\le}2), mixed-l Rydberg series, from which we obtain an improved value of the CaF ionization potential, 47 005\ifmmode\pm\else\textpm\fi{}20 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$. All previously observed low Rydberg and valence states of CaF fit smoothly into these six Rydberg series, which form the complete set of l\ensuremath{\le}2 series. Using this information, absolute quantum defects have been determined and the series are assigned nominally (i.e., dominant l character) as d (\ensuremath{\Delta}, \ensuremath{\Pi}, and \ensuremath{\Sigma}), p (\ensuremath{\Pi} and \ensuremath{\Sigma}), and s (\ensuremath{\Sigma}).