Far-wing profile of photoabsorption spectra of Na(3s-3p) atoms perturbed by helium

The far wings of the sodium spectra arising from the collisional broadening of the D lines by ground helium atoms are investigated theoretically. The required X-2 Sigma(+), A(2) Pi and B-2 Sigma(+) potential-energy curves and transition dipole moments have been generated from ab initio CASSCF-MRCI calculations to determine, within the framework of the semiclassical and full quantum-mechanical approaches, the temperature-dependent photoabsorption spectra. The profile is dominated by the free-free transitions at all temperatures ranging from 500 K to 3000 K and the computations show the existence of a satellite structure in the blue wing attributed to the X -> B transitions. The satellites occur around the wavelength position 520 nm when the calculations are performed classically and around 528 nm when they are performed quantum mechanically. The results are in good accordance with those produced by other theoretical and experimental works.