Intensity modifications in the spectrum of mercury

Abstract

Intensity modifications are noted in the high-frequency spectrum of mercury in the region λ7000 to λ2400. All the singlet series are strengthened. In the triplets the first members of the series are weakened by self-absorption. Those intercombination lines which begin on singlet levels are strengthened, whilst those which begin on triplet levels are weakened. The unclassified lines show three types of behaviour, namely strengthening, weakening, or freedom from change. It is suggested that the strengthened unclassified lines begin on singlet levels, and the weakened on triplet levels, and that the unchanged lines are due to displaced triplet levels in the excited atom. The unclassified lines are thus broadly divided. The degree of intensity modification can be made to vary by alteration of the current density in the discharge tube. Mercury films are produced by the discharge driving mercury into the walls of the tube. These are described and suggestions made as to their nature. The line 61P1 - 81S0, namely λ4916, is examined for fine structure with a resolving power of over 3 × 106. It is quite single and very narrow, the half-width being less than 0.004 A.U. The intensities of the satellites in λ5461 are found to be altered by self-absorption.