Assessment of the deviation of the collisional rate coefficients (in units of cm³ s⁻¹). The left-hand panel shows the discrepancies generated by the extrapolation method relative to the close-coupling scattering data computed in this work. The right-hand panel compares the HC₃N and HC₅N, HC₃N, and HC₇N, and HC₅N and HC₇N CC rate coefficients. The solid line represents a 1:1 ratio, while the dashed lines delimit a region where the agreement is within a factor of two.