Basis set aug-cc-pVTZ

From the values obtained by the larger basis sets (AUG-cc-pVTZ, AUG-cc-pVTQZ), it is evident that the convergence is reached already at 6-311++G level. The use of TZVP valence basis set gives also results in excellent agreement with experimental evidences (the deviation is of 0.4 kcai/mol). On the basis of these results this same set TZVP has been used in connection with other exchange-correlation functionals. 

Stuttgart pseudopotential for Au with a uncontracted (lls/10p/7d/5f) valence basis set and a Dunning augmented correlation consistent valence triple-zeta sets (aug-cc-pVTZ) for both C and N, but with the most diffuse f function removed, was used. 

Fig. 7. Distance-dependent potential energy curves for the anunonia adduct to the silyl cation, H3N"-SiH3 at different levels of correlated wavefunctions density functional theory (DFT-B3LYP) with a basis set of triple-zeta quality (aug-cc-pVTZ), MP2 as well as MP4 perturbation, and coupled cluster CCSD(T) calculations with double-zeta basis sets (aug-cc-pVDZ).

Li et alP reported a theoretical study of the structure and interaction-induced dipole moment, mean polarizability and mean first hyperpolarizability of the NH3-HCl-(H20)n (n = 0 ) clusters. They relied on B3LYP calculations with large standard basis sets aug-cc-pVDZ, aug-cc-pVDZ-fBF (aug-cc-pVDZ augmented with suitable placed bond functions), aug-cc-pVTZ, d-aug-cc-pVDZ and t-aug-cc-pVDZ. The authors have reached important conclusion on the magnitude of electric properties. For the non-hydrated complex NH3-HCI the first hyperpolarizability, calculated with the d-aug-cc-pVDZ basis, is jS = — 3.35 e ao Eh while the respective result for NH3-HCI-H2O is 413.52 and increases to 886.41 for NH3-HC1-(H20)4. 

We will now look at how different types of wave functions behave when the O-H bond is stretched. The basis set used in all cases is the aug-cc-pVTZ, and the reference curve is taken as the [8, 8J-CASSCF result, which is slightly larger than a full-valence Cl. As mentioned in Section 4.6, this allows a correct dissociation, and since all the valence electrons are correlated, it will generate a curve close to the full Cl limit. The bond dissociation energy calculated at this level is 122.1 kcaPmol, which is comparable to the experimental value of 125.9 kcal/mol. 

From a basis set study at the CCSD level for the static hyperpolarizability we concluded in Ref. [45] that the d-aug-cc-pVQZ results for 7o is converged within 1 - 2% to the CCSD basis set limit. The small variations for the A, B and B coefficients between the two triple zeta basis sets and the d-aug-cc-pVQZ basis, listed in Table 4, indicate that also for the first dispersion coefficients the remaining basis set error in d-aug-cc-pVQZ basis is only of the order of 1 - 2%. This corroborates that the results for the frequency-dependent hyperpolarizabilities obtained in Ref. [45] by a combination of the static d-aug-cc-pVQZ hyperpolarizability with dispersion curves calculated using the smaller t-aug-cc-pVTZ basis set are close to the CCSD basis set limit. 

Combining [52] the zero point vibrational corrections of Ref. [51] with the CCSD results obtained in the t-aug-cc-pVTZ and d-aug-cc-pVQZ basis sets we obtained the estimates for the ZPV corrected 70, A and B coefficients listed in Table 4. An experimental estimate for 70, A, and B has been derived by Shelton by fitting the results of ESHG measurements to the expresssion = To(l + A0JI2 + This... 

FIGURE 2.1 Geometries of the reactants (11-16) and transition structures (S1-S6) at B3LYP level of theory in gas phase, using 6-3 lG(d), 6-311+ G(d,p) (bold characters), 6-311+ G(d,p), S(2df) (underlined), aug-cc-pVTZ (italic) basis sets, and in aqueous solution at B3LYP-C-PCM/6-311 + G(d,p) level of theory (bold characters in parenthesis). Bond length data have been taken from Ref. [13]. 

G(d,p), both intermediate and TS geometries become more reliable, at least as judged from a comparison with the corresponding geometries achieved using the augmented correlation-consistent polarized valence triple-zeta (aug-cc-pVTZ) basis sets.32... 

This observation suggested that refining energies by single-point calculations with the aug-cc-pVTZ basis set on 6-311 + G(d,p)-optimized geometries is a reliable practice. 

These basis sets consist of 34 (6-311+G(d,p)), 92 (aug-cc-pVTZ), 172 (aug-cc-pVQZ), and finally 287 (aug-cc-pV5Z) contracted Gaussian functions and include polarization functions up to d- (6-311+G(d,p)), f- (aug-cc-pVTZ), g- (aug-cc-pVQZ), and even h-character (aug-cc-pV5Z). 

Table 12-2. Experimental values and deviation from experiment of the R0 H bond distance, the symmetric (vs) and the antisymmetric (vas) stretching frequency [cm-1], the dipole moment [D], and the mean polarizability [A3] of the water molecule. The aug-cc-pVTZ basis set is used throughout. 

Table 12-6. Harmonic frequency shifts [cm 11 of the donor O-H stretching mode and elongation of the O-H bond [A] in the water dimer computed at several levels of theory (aug-cc-pVTZ basis set). 

Table 1 Calculated equilibrium bond distances [A] of the dihalogens as obtained with different methods applying the aug-cc-pVTZ basis set [35]...

---