Direct examination of complex cluster configurational spaces at a desired, high level of theory costs an immense amount of computational resources. Hence, the most common general strategy for configurational sampling (CS) is the so-called bottom-up approach, as illustrated in (Figure ). This approach is sometimes also referred to as the "building up" principle, but should be distinguished from strategies where the properties of the 𝑁-cluster need to be known to calculate the properties of the (𝑁 + 1)-cluster (an example of such a method is that introduced by Kildgaard et al. to study the hydration of dry molecular clusters). The bottom-up approach explores the configurational space using fast but less accurate methods, where only promising candidates are carried through several steps of reoptimization at higher levels of theory and filtering up to the desired level of theory. This methodology determines the workflow of the JKCS scripts: