Wave numbers and Ar pressure-induced shifts of¹⁹⁸Hg atomic lines measured by Fourier transform spectroscopy

Wave numbers and argon-pressure-induced shifts of mercury emission lines were measured using a UV/visible Fourier transform spectrometer (FTS). The observations were made with electrodeless lamps containing isotopically pure 198 Hg and argon buffer gas at pressures of 33 Pa (1/4 Torr), 400 Pa (3 Torr), 933 Pa (7 Torr) and 1333 Pa (10 Torr). Calibration of the FTS wave number scale was obtained from the four most prominent 198 Hg lines (6p 3 P 2 –7s 3 S 1 at 546.2 nm, 6p 3 P 1 –7s 3 S 1 at 436 nm, 6p 3 P 0 –7s 3 S 1 at 404.8 nm and 6p 3 P 2 –6d 3 D 3 at 365.1 nm), enabling measurements of wave numbers and argon pressure shifts of other UV and visible mercury transitions with high accuracy. Our measurements provide new data for the wave numbers and pressure-induced shifts of 20 mercury lines. The wave numbers of mercury lines emitted from the 400 Pa (3 Torr) lamp can be used as standards for wavelength calibration in inductively coupled plasma (ICP) spectrochemical analysis or in experiments where medium-resolution monochromators are used. The pressure-induced shifts of the 198 Hg emission lines are in reasonable agreement with theoretical predictions and could be of interest for validating calculations of mercury–argon interactions.