Our approach requires three steps as described briefly in the following; details are given in the Supporting Information. All quantum chemical calculations were performed using the ORCA 5.0 program suite (see SI, Method S1). (1) A DFT geometry optimization and frequency calculation is carried out; here, TPSS/def2-TZVP:def2-SVP (heteroatoms:carbon, hydrogen) is chosen as the theory level. (2) Using Wigner sampling as implemented in the SHARC program, an ensemble of displaced structures is created that is representative for a given temperature (see SI, Method S2); here, 600 structures are generated per temperature of interest (see SI, Figure , for convergence behaviour).