Interpolating Hamiltonians in chemical compound space

We analyze the Hamiltonian‐interpolating schemes in chemical compound space. We show that if one allows for system‐dependent information there are trivial solutions to this problem that allow to linearly interpolate between any two given iso‐electronic Hamiltonians. If, on the other hand, one do not use any information about the system's Hamiltonians, we prove that there are no system‐independent multiplicative interpolating procedures that linearize the energy. The alchemical exploration of chemical compound space (CCS) has proven to be a powerful tool to study a plethora of chemical phenomena. Recently, much effort has been devoted to find more efficient ways to navigate in CCS, with particular emphasis on linear interpolating methods. This contribution shows that there are no multiplicative system‐independent interpolation schemes in CCS.