Total rate constants k as a function of temperature T for the reaction of He^+⋅ with CH₃CN. Solid red line: our model, solid black line: Langevin model, cyan line with dots: KIDA database (Wakelam et al. 2015; Su & Chesnavich 1982), blue line with triangles: UMIST database (Millar et al. 2024), dashed blue line: scaled averaged dipole orientation (ADO) with $c=\overline{\cos \theta }=0.253$ (Bass et al. 1975; Su et al. 1978), dashed magenta line: average cosθ method (Kosmas 1984), dashed brown line: statistical adiabatic channel model (SACM), Eq. (5.2) from Troe (1996).