Absorption spectrum of Si i between 1500 and 1900 Å

The absorption spectrum of Si i in the wavelength region 1500–1900 Å has been photographed at high resolution. The silicon vapor was produced in a 122-cm-long King furnace at 1800–2300 °C. Forty-two Rydberg series have been observed from the ground-state terms 3p2 3P and 1D to terms associated with the 3pns and 3pnd configurations. All of the series from these configurations with J < 4 have been extended with the 3pnd3D3° levels reaching n = 56. Numerous perturbations have been observed. Some initial correlations with recent rocket solar spectra in this wavelength range are illustrated. Lists of wavelengths, intensities, and derived energy levels are presented. An ionization limit of 65 747.55 ± 0.21 cm−1 has been determined from the nd3D3° series.