Temperature dependences of the six collisional line-shape parameters, γ₀, δ₀, γ₂, δ₂, ${\tilde{v}}_{\text{opt}}^r$, and ${\tilde{v}}_{\text{opt }}^i$, of the R(0) 0-0, R(1) 0-0, and R(2) 0-0 lines of HD perturbed by H₂. The red and black curves are the ab initio results and DPL approximations, respectively. The small panels show the residuals from the DPL fits. The vertical axes for all the panels (including residuals) are in [10⁻³ cm⁻¹ atm⁻¹.