Theoretical Study of Sodium and Potassium Resonance Lines Pressure Broadened by Helium Atoms

Abstract

We perform fully quantum mechanical calculations in the binary approximation of the emission and absorption profiles of the sodium $3s$-$3p$ and potassium $4s$-$4p$ resonance lines under the influence of a helium perturbing gas. We use carefully constructed potential energy surfaces and transition dipole moments to compute the emission and absorption coefficients at temperatures from 158 to 3000 K. Contributions from quasi-bound states are included. The resulting red and blue wing profiles agree well with previous theoretical calculations and with experimental measurements.Comment: 16 figure