TPSS functional

We now compare the PM3-D method with previous uncorrected DFT calculations on the S22 complexes [130], For the dispersion-bonded complexes the errors in the interaction distances for the PBE, B3LYP and TPSS functionals are reported to be 0.63, 1.16 and 0.69 A which are reduced to 0.17, 0.00 and 0.02 A when appropriate dispersive corrections are included. We see in Table 5-9 that the PM3-D method is capable of predicting the structures of dispersion-bonded complexes with greater accuracy than some uncorrected DFT functionals and with an accuracy comparable to that for the dispersion corrected PBE functional [130],... 

Table 7.7 Barriers and reaction energies (relative energies for reactant, transition state, product) calculated for the B3LYP, M06, and TPSS functionals using the 6-31G, 6-311+G, and 6-311++G(2df,2p) basis sets (shown respectively from top to bottom line). The barrier is the free energy of activation at 298 K and the reaction energy is the free energy of reaction at 298 K, in kJ mol-1. Cf. Table 7.6 and Table 5.11...

The discrepancies between the calculated values of —eHOMO and experimental ionization potentials are frequently attributed to self-interaction error. Indeed, applying the Perdew-Zunger technique4 to correct this error of the LDA-, GGA-(PBE), and meta-GGA (TPSS) functionals improves the numerical values of —8HOmo-98 Interestingly, these studies showed that the Perdew-Zunger correction does not improve ionization potentials and electron affinities if calculated as energy differences (ASCF). 

The hybrid TPSS functional (TPSSh) [180] is also given by Eq. (187) with DFT = TPSS and the mixing parameter oq = 0.10, which was determined by minimizing the MAE in the enthalpies of formation of 223 G3/99 molecules. TPSSh satisfies the same... 

In order to assess the performance of the OS global hybrid functionals from a different point of view, we also compare the orbital energies and IPs of valence and core orbitals for OCS molecule in a sense of Koopmans theorem. IPs obtained by the OS hybrid functionals are shown in Table 14.16. The deviations from experimental IPs [53] and values of a, are shown in parentheses and square brackets, respectively. For HOMO, the OS global hybrid functionals provide comparatively similar IPs 11.45,10.99, 11.18, and 11.17 eV for SVWN5, BLYP, PBE, and TPSS functionals, and the corresponding deviations are at most 0.25 eV. The OS hybrid functionals also reproduce Ols and Sis IPs within the deviation of 2.5 eV for the LDA, GGA, and meta-GGA functionals, though the accurate estimation of large IPs is rather difficult. 

Table 14.16 OCS IPs (eV) by OS global hybrid functionals of SVWN5, BLYP, PBE, and TPSS functionals and Oj determined for the OS in eV...

The TPSS (meta-GGA) fimctional is somewhat difiicult to assess. For lattice constants, it is significantly better than LDA and GGA with an error of only 0.5%, getting aU four metals within 0.04 A. For the bulk moduh, however, it is not as accurate, with an error of 11%, and for , we are not aware of any reported values. There is now a revised TPSS functional, which for many properties improves over the original TPSS functional [35]. 

The TPSS functional appears to offer equivalent performance to PBE for lattice constants and bulk moduli. For TPSS actually appears to be slightly... 

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