BHLYP functionals

A proper description of interfacial electronic properties requires going beyond a simple two-molecule representation containing one donor and one acceptor unit [10]. In order to assess the validity of LRC functionals for systems of large size, we have computed the evolution of the HOMOxtf and LUMOtcnq in isolated one-dimensional stacks containing from one to live layers. We compared the coB97X functional, which gave the most reliable results in the previous section, to the BHLYP functional that also... 

Tab. 12.1. Total interaction energies Ei of the multiply-hydrogen-bonded complex in Fig. 12.2 in kJ mol. BHLYP is a hybrid density functional which features 50% admixture of exact Hartree-Fock-type exchange, AMI and PM3 are semi-empirical models, which are an efficient approximation to the Hartree-Fock method, and CCSD is a coupled-cluster model.

The BLYP/6-31G and BP/86 (and probably the pBP/DN ) correction factors are very close to unity. For the frequencies of polycyclic aromatic hydrocarbons calculated by the B3LYP/6-31G method, Bauschlicher multiplied frequencies below 1300cm by 0.980 and frequencies above this by 0.967 [58]. In their paper introducing the modification of Becke s hybrid functional to give the B3LYP functional, Stephens et al. studied the IR and CD spectra of 4-methyl-2-oxetanone and recommended the B3LYP/6-31G as an excellent and cost-effective way to calculate these spectra [49]. With six different functional. Brown et al. obtained an agreement with experimental fundamentals of ca. 4-6%, except for BHLYP [77]. 

Figure 12.1 Performance of different functionals in the calculation of F shielding for the series of diamagnetic tf complexes UFnCI (n = 1 — 6). BP-ref, B3LYP-ref, and BHLYP-ref are DFT results employing a scalar relativistic effective core potential for U, from Straka and Kaupp 143], The other data are from all-electron scalar ZORA calculations with NWChem by Aquino et al. [15], CAM and LC indicates hybrid functionals with range-separated exchange. The straight black line indicates where calc = expt. Absolute shielding constants converted from experimental shifts taken from Straka and Kaupp [43], Figure reprinted with permission from Aquino et al. [15]. 2011 American Chemical Society. See color plate section...

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