Interferometric measurements of isotope shifts in the visible region of a number of lines of singly and doubly ionized mercury have been made from sources containing enriched isotopes Hg<sup>198</sup>, Hg<sup>200</sup>, and Hg<sup>202</sup>. In particular those lines having large isotope shifts were carefully studied. The results indicate a constant value, within experimental limit, of the ratio of the shift of Hg<sup>198</sup>–Hg<sup>200</sup> to that of Hg<sup>200</sup>–Hg<sup>202</sup>.
R. W. SHORTHILL and G. R. FOWLES, "Interferometric Measurements of Isotope Shifts in Mercury II and Mercury III with Enriched Isotopes," J. Opt. Soc. Am. 48, 459-459 (1958)