A new fully quantum-mechanical method used to calculate the collisional broadening coefficients and shift coefficients of Rb D₁ lines perturbed by noble gases He and Ar

In this work, a new full quantum method is proposed to calculate the broadening and shift coefficients of the D₁ line in neutral collision. Based on the variable phase approach and Baranger theory, this method calculates the scattering phase shift instead of scattering matrix elements in order to simplify the calculation. As an illustration, this method is used to calculate the broadening and shift coefficients of the absorption lines of alkali metal atom Rb, as it collides with buffer gas He and Ar, in a temperature range from 150 K to 800 K. With a comparison with other calculations and experiment measurements, the reasonable agreements in all cases demonstrate the validity and simplicity of this method.