Spectrum and term system of neutral nickel, Ni I

Abstract

Spectra of nickel, emitted from hollow cathode discharges, have been recorded in the region 1700-55000A (58 800-1800cm-'). Fourier transform spectrometers were used above 1800A, yielding very high accuracy and resolution. The number of classified NiI lines has increased from 1071 to 1996. 289 of the lines have been resolved in 2-4 isotope components. The term system derived from the observations comprises 286 energy levels. The term structure and the coupling conditions have been studied by means of ab initio and parametric theory.

The elemental composition of the Sun

“…Compared to the result we reported in AGSS09 (log Ni = 6.22 ± 0.04), our result here is slightly lower because we employed new g f -values and an expanded set of isotopic separations from Wood et al (2014b) (in AGSS09 andScott et al 2009 we used g f -values from Wickliffe & Lawler 1997 and isotopic separations from Litzen et al 1993). Improvements in the overall opacity, equation of state, ionisation potential and partition function also play a small role in the difference from AGSS09.…”

“…We obtained Ni  wavelengths and excitation potentials from Litzen et al (1993). Transition identities came from Wickliffe & Lawler (1997), except for Ni  481.2 nm, where the transition designation is from VALD (Kupka et al 1999).…”

“…Much of the power of that analysis can be attributed to the accurate FTS wavelengths of 58 Ni and 60 Ni line components recorded by Litzen et al (1993) Table 2.…”

Theoretical prediction of noble-gas compounds: Ng–Pd–Ng and Ng–Pt–Ng

“…Similarly, the binding energy for Ni-Ng n should be estimated relative to the dissociation limit, Ni ͑ 3 F͒ + nNg. The experimental excitation energy for 1 S state of Ni atom relative to the ground 3 F 4 state is reported as 42.1 kcal/ mol, 53 which is much larger than the expected stabilization energy for Ni-Ng 2 . This consideration suggests that it is difficult to detect Ni-Ng 2 compounds in the experiment.…”

The [ITAL]Forbidden[/ITAL] Abundance of Oxygen in the Sun

“…The blending Ni i line's wavelength was measured as 6300.339Å by Litzén, Brault, & Thorne (1993) with an estimated uncertainty of 2 to 3 mÅ. Litzén et al's energy levels derived from their extensive reinvestigation of the Ni i spectrum predict 6300.342Å for the line.…”