The present study deals with the collisional broadening of monatomic magnesium, evolving in a helium buffer gas, in the wavelength and temperature ranges 260–310 nm and 100–3000 K, respectively. The computed emission and absorption spectral profiles are based on the most recent potential-energy curves and transition dipole moments. The required interatomic Mg$(3s^2)+\mathrm{He}(1s^2)$ and Mg$(3s3p)+\mathrm{He}(1s^2)$ potentials are constructed from two different sets. The purpose of this treatment is twofold. First, using the quantum-mechanical Baranger impact approximation, the width and shift of the line-core spectra are determined and their variation law with temperature is examined. Then, the satellite structures in the blue and red wings are analyzed quantum mechanically. The calculations show especially that the free-free transitions contribute most to the MgHe photoabsorption spectra and that a satellite structure is observable beyond the temperature $1800\hspace{0.5em}\mathrm{K}$ around the wavelengths $272$ or $276\hspace{0.5em}\mathrm{nm},$ depending on the used potential set. Weak satellites have also been investigated and, for all cases, the obtained results showed good agreement with those already published.

• Received 29 August 2010

DOI:https://doi.org/10.1103/PhysRevA.83.032719