Wavelengths and isotope shifts for lines of astrophysical interest in the spectrum of doubly ionized mercury (Hg iii)

Wavelengths and isotope shifts have been measured for the 1738.4-, 1738.5-, 1740.2-, and 2354.2-Å lines of Hg i i i with an uncertainty of 0.002 Å. The lines were excited in a pulsed radio-frequency discharge and observed with a 10.7-m normal-incidence vacuum spectrograph. Observations were made with lamps containing natural Hg, ${}_{}{}^{198}{}_{}{}^{}\mathrm{Hg}$, and ${}_{}{}^{204}{}_{}{}^{}\mathrm{Hg}$. By using well-established relative isotope shifts, wavelengths of these four lines for ${}_{}{}^{196}{}_{}{}^{}\mathrm{Hg}$, ${}_{}{}^{200}{}_{}{}^{}\mathrm{Hg}$, ${}_{}{}^{202}{}_{}{}^{}\mathrm{Hg}$, and the centers of gravity for ${}_{}{}^{199}{}_{}{}^{}\mathrm{Hg}$ and ${}_{}{}^{201}{}_{}{}^{}\mathrm{Hg}$ were also determined. The results provide important data for determining elemental and isotopic abundances of Hg from spectra of Hg-rich chemically peculiar stars.