Wavelengths of Forbidden Transitions Arising from Levels Within the Fe⁺¹⁹ 2S²2P³ Ground Configuration

Abstract

In this paper we report the identification of all remaining unidentified forbidden lines arising from transitions within levels of the Fe⁺¹⁹ ground configuration. These lines were identified using data from the SOHO/SUMER spectrograph and Skylab. Adjusted wavelength values are also given for some previously observed lines. Forbidden lines that are the result of transitions within levels of the ground configuration of a highly ionized astrophysically abundant element generally have longer wavelengths than resonance lines emitted by the same ion. Many of these forbidden lines are fairly prominent in low-density plasmas and traditionally have been used in determining properties of high-temperature astrophysical plasmas. The identified Fe⁺¹⁹ forbidden lines span the 300-2665 Å wavelength range. Since spontaneous decay rates of forbidden transitions arising from the same upper level are known quite accurately, these lines can be used for calibrating spectrometers over wide wavelength ranges.