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** DFT, in calculating geometries effects **

** DFT, in calculating geometries heterocycles **

** DFT, in calculating geometries insensitivity with respect to multireference **

Theoretically calculated electron affinities were computed with the DFT method at the pBP86/DN //DN level by subtraction of the total energy of the parent molecule from that of the electron adduct in the geometry of the parent molecule. The electrostatic attraction of the positively charged intercalators increases the gas- phase EA artificially. The relative values should be considered [Pg.114]

Florian and Johnson50 calculated vibrational frequencies in isolated formamide using the DFT calculations at the LDA (SVWN) and post-LDA (B88/LYP) levels. The DFT frequencies were compared with the ones derived from the Hartree-Fock and MP2 calculations, and from experiment. The authors found that the DFT(B88/LYP) frequencies were more in line with experiment then the MP2 ones. The DFT(SVWN) calculations led to geometry, force constants, and infrared spectra fully comparable to the MP2 results. The equilibrium geometry and vibrational frequencies of formamide were also the subject of studies by Andzelm et al.51. It was found that the DFT(B88/P86) calculations led to frequencies in a better agreement with experiment than those obtained from the CISD calculations. [Pg.91]

A comparison between Gl, G2, G2(MP2) and G2(MP2,SVP) is shown in Table 5.2 for the reference G2 data set the mean absolute deviations in kcal/mol vary from 1.1 to 1.6 kcal/mol. There are other variations of tlie G2 metliods in use, for example involving DFT metliods for geometry optimization and frequency calculation or CCSD(T) instead of QCISD(T), with slightly varying performance and computational cost. The errors with the G2 method are comparable to those obtained directly from calculations at the CCSD(T)/cc-pVTZ level, at a significantly lower computational cost. [Pg.166]

The success of the PP functional in calculating geometries and highly accurate hyperfine structures has also been shown by Barone et al, in their investigation of fluorinated vinyl radicals [31, a]. Other LCAO-DFT studies of hyperfine structures involve LDA (Xa) calculations on the VN system by Mattar and Doleman [31, b]. There, a deviation from experiment is clearly shown, which most likely can be cured by the gradient corrections. [Pg.317]

** DFT, in calculating geometries effects **

** DFT, in calculating geometries heterocycles **

** DFT, in calculating geometries insensitivity with respect to multireference **

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