Benchmarking Density Functional Methods for Calculation of State Energies of First Row Spin-Crossover Molecules [component]

unpublished
A systematic study of the performance of several density functional methodologies to study spin-crossover (SCO) on first row transition metal complexes is reported. All functionals have been tested against several mononuclear systems containing first row transition metal complexes and exhibiting spin-crossover. Among the tested functionals, the hybrid meta-GGA functional TPSSh with a triple-z basis set including polarization functions on all atoms provides with the best results across different
more » ... metals and oxidation states, and its performance in both predicting the correct ground state and the right energy window for SCO to occur is quite satisfactory. The effect of some additional contributions, such as zeropoint energies, relativistic effects and intramolecular dispersion interactions, has been analyzed. The reported strategy thus expands the use of the TPSSh functional to other metals and oxidation states other than Fe II , making it the method of choice to study SCO in first row transition metal complexes. Additionally, the presented results validate the potential use of the TPSSh functional for virtual screening of new molecules with SCO, or its use in the study of the electronic structure of such systems. possibility of SCO to occur for such type of molecules. Nevertheless, these models are often constrained to specific systems, and lack transferability, and therefore, a first principles approach to the design of new SCO systems will be highly desirable. However, theoretical modeling of SCO systems can be quite challenging. 32 On one hand, the electronic energy difference between both spin-states can be accurately computed using post-CASSCF methods, such as CASPT2, [35] [36] [37] or post Hartree-Fock methods such as mutirreferent Coupled Cluster type calculations (CC). 38 Such calculations have been successfully used in the study of selected systems, but they tend to be computationally expensive and system dependent. [39] [40] [41] [42] The alternative to this will be the use Density Functional Theory (DFT) methods.
doi:10.1021/acs.inorgchem.8b01821.s001 fatcat:ygy5znbj4zda5g72hlya7ckjra