As shown in Fig. , collisions are the dominant process below 2 THz, while decay channels become available from ~2 THz, and the 𝑁 ̅ 2 (1) (𝜔) and 𝑁 ̅ 2 (2) (𝜔) are comparable around 4 THz. The number of collision pathways falls to zero from ~6-8 THz, and decay processes dominate at higher frequencies. The five filled models show significant changes in the number of collision channels over the 2-6 THz region where the largest reduction in the 𝜅 latt is observed (c.f. Fig. ), while KrCo8Sb24 and XeCo8Sb24 also show an increase in the number of decay channels between 4-6 THz. Similar differences are seen at 600 K (see Figure .24), but both w-JDoS functions are scaled by a factor of two due to the larger phonon occupation numbers.