DFT and Hybrid Approaches for Organometallic Systems

B3LYP B3LYP-D B97-1 HSE06 PBEO CAM-B3LYP M06 B97X bB97 B97XD LC- o)PBE M06-2X 

All DFT computations have been performed with basis sets of at least double- plus polarization quality, mainly the SNSD/N07D 

Feasible computations of spectroscopic properties for even larger systems can be faciUtated thanks to the set up of relatively small, purposely tailored basis sets, that allow to reach an accuracy similar to that obtainable with much larger basis sets (e.g., aug-cc-pVTZ) even for difficult properties such as Raman intensities [132] or rotatory strengths [133]. An example is provided by the recently introduced spectroscopic aug-N07D/SNSD basis set [49, 94, 134]), developed also for some metallic atoms (Li, Be, B, Na, Mg, Al, Zn). The SNSD [120, 134] basis set is an improved version of the polarized double- N07D basis set [94-96, 

obtained by consistently including diffuse s functions on all atoms, one set of polarized li-functions on heavy atoms (p on hydrogens), and Stuttgart-Dresden electron core pseudopotentials [135, 136] for atoms beyond the third row of the periodic table. 

Another route to obtain accurate results, even for relatively large molecular systems (few dozens of atoms), is provided by hybrid QM models [137], which combine cheap electronic structure approaches (especially DFT models) with a posteriori refinement of selected properties at higher level of theory (for a set of representative examples, the reader is referred to to Refs. [49, 118, 138-140]). 

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