Basis Pople-type

A method which is similar to the Pariser-Parr-Pople method for the n electron system and is applicable to common, saturated molecules has been proposed by Pople 28>. This method is called the CNDO complete neglect of differential overlap) SCF calculation. Katagiri and Sandorfy 29> and Imamura et al. °) have used hybridized orbitals as basis of the Pariser-Parr-Pople type semiempirical SCF calculation. 

Pople-type basis sets are generally characterized by heavier contraction (that is, fewer contracted functions for a given primitive set) and consequently somewhat lower accuracy. The earliest set was a minimal basis contraction (STO-3G) of a... 

Scheme 7.1 Isodesmic equation for the conversion of methane and propane into ethane (the abbreviation for the theoretical method, B3LYP/6-31 G(d), indicates the use of Becke s three-parameter hybrid exchange functional with the Lee-Yang-Parr correlation functional and a double-f Pople-type split valence basis set with one set of d-type polarization functions).

The choice of a basis set can be crucial and is particularly important for post-HF methods. HF itself and DFT methods are not so basis set dependent, but this should not be taken as an excuse for not checking a few basis sets even for these levels. The popular Pople-type basis sets [26], e.g. 6-31G(d), have proven their value for HF and DFT, and are well behaved for structures involving first row and many heavier elements. The cc-p VXZ b asis sets [ 19 ], which are also sometimes used in conjunction with DFT computations, were explicitly designed to recover as much correlation energy as possible for highly correlated methods and are, therefore, not necessarily guaranteed to perform well with DFT methods. 

Bauschlicher, C. W. J. and Partridge, H., A comparison of correlation-consistent and Pople-type basis. sets, Chem. Phys. Lett. 245, 158-164 (1995). 

Denis PA (2005) Basis set requirements for sulfur compounds in density functional theory a comparison between correlation-consistent, polarized-consistent, and Pople-type basis sets. J Chem Theory Comput 1 900-907... 

Basis sets STO-3G through 6-311G are Pople-type basis sets and are referenced in the text. 

As an application we calculated electronegativity and hardness values. For a series of 22 atoms, including cations, we obtained the following average deviations (in eV) from the "experimental" values, estimated via (11), using a large Pople type basis set (6-311++G(3df,2p) [34]... 

Study with Extended Pople-Type Basis Sets.473... 

We now examine the results when a set of larger Pople-type basis sets is used. These are based on a triple-zeta valence description. The effects of adding diffuse functions and using multiple sets of polarization effects are considered. The 6-311G basis set is a triple-zeta valence basis set, augmented with a set of polarization functions for all atoms. 6-311++G includes in addition a set of diffuse functions on aU atoms. In the 6-311++G(2df,2pd) and 6-3U++G(3df,3pd), multiple sets of polarizations are used on all atoms. 

NH3(g) using extended Pople-type basis sets (units are... 

We performed the benchmark calculations of DFT+ALL methods in order to assess applicability. We used the CCst, GCst, and GGst proposed in JSCH-benchmark sets [34], where the most accurate computations were performed with approximated CCSD(T)/CBS-limit level of theory. We compared these references with the results of DFT+ALL methods in several basis sets. Pople-type basis sets (6-31G,6-31G(d,p),6-31++G(d,p),6-311+G(d,p),6-311++G(df,pd) were used for this benchmark. We estimated the stacking energy between C (or G) and C (or G). By means of in the conventional DFT, HF, and MP2 methods, we estimated the stacking energy defined as... 

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