Split valence polarization

Basis Set Type Minimal Split-valence Polarized Diffuse High ang. momentum... 

The main difference between the G2 models is tlie way in which tlie electron correlation beyond MP2 is estimated. The G2 method itself performs a series of MP4 and QCISD(T) calculations, G2(MP2) only does a single QCISD(T) calculation with tlie 6-311G(d,p) basis, while G2(MP2, SVP) (SVP stands for Split Valence Polarization) reduces the basis set to only 6-31 G(d). An even more pruned version, G2(MP2,SV), uses the unpolarized 6-31 G basis for the QCISD(T) part, which increases the Mean Absolute Deviation (MAD) to 2.1 kcal/mol. That it is possible to achieve such good performance with tliis small a basis set for QCISD(T) partly reflects the importance of the large basis MP2 calculation and partly the absorption of errors in the empirical correction. 

SHA svp Schaffer Horn Aldrich split valence polarization constant... 

Ground-state geometries of 7AI(H20) =i 5 complexes in the gas phase were optimized with the second-order M0l-ler-Plesset Perturbation Theory (MP2) with the resolution-of-the-identity (RI) approximation for the electron repulsion integrals [48, 49]. The split valence polarized (SVP)... 

BP = Becke-Perdew DFT functional B3LYP = modified BLYP 10 = input-output RI = resolution of the identity RPA = random phase approximation SCI = single.s Cl SV = split valence SVP and SV(P) = split valence polarization TZVP = triple zeta valence polarization. 

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