Interatomic Potentials of Cd - He from Far-Wing Line Shapes

Abstract

The intercombination absorption line of the Cd (326.1 nm) line broadened by pressure effects of He in the spectral range extending from 1400 cm-1 in the blue wing to 2000 cm-1 in the red wing was studied using a high resolution spectrometer. The temperature dependence of the studied line was analyzed in the framework of the quasi-static theory. This analysis allowed us to determine the ground (X10+), and the excited (31, 30+) state potentials at internuclear separations from 3.3 Å to 5.5 Å. The well depths with their positions for these states are respectively equal to (16.3 ± 2 cm-1, 4.5 ± 0.2 Å), (2.55 cm-1, 4.94 ± 0.3 Å) and (45.8 ± 3 cm-1, 3.8 Å). These values are in close agreement with those obtained for this mixture (Cd - He) from other experimental methods. The van der Waals coefficient differences between the ground 10+ state and the two exited states 30+ and 31 (ΔC60 and ΔC61) are obtained from the near red wing profile using Kuhn's law. The values of ΔC60 and ΔC61 are found to be equal to 14.8 ± 2 and 28.5 ± 3 eV Å6 respectively.