Isotope-Selective Laser Analysis of the Electron-Impact Excited6S01→6P11Transition of Mercury: A Test of the Percival-Seaton Hypothesis

Abstract

An isotope-selective technique has been used to measure line polarizations in the range 7.5 to 12.0 eV for the electron-impact-excited 185-nm transition of atomic mercury. Measurements were made on the $I=0\mathrm{}$ and $I=\frac{1}{2}$ nuclear-spin isotopes. A stepwise excitation technique was used involving electron excitation followed by single-mode laser excitation. The results obtained indicate a breakdown in the Percival-Seaton hypothesis near threshold.