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6-311+G(2df,2p) In summary; the 6-31G* basis set (defined for the atoms H through Zn) is a split-valence double-zeta polarized basis set that adds to the 6-31G set five d-type Cartesian-Gaussian polarization functions on each of the atoms Li through Ca and ten f-type Cartesian Gaussian polarization functions on each of the atoms Sc through Zn.
The effect of diffuse functions is assessed using an MP4 calculation with the 6-311+G(d, p) basis set. The largest basis set is 6-311+G(3df,2p) used at the MP2 level of theory. A Hartree–Fock geometry optimization with the 6-31G(d) basis set used to give a geometry for: A frequency calculation with the 6-31G(d) basis set to obtain the zero ...
STO-nG basis sets are minimal basis sets, where primitive Gaussian orbitals are fitted to a single Slater-type orbital (STO).originally took the values 2 – 6. They were first proposed by John Pople. A minimum basis set is where only sufficient orbitals are used to contain all the electrons in the neutral atom. Thus for the hydrogen atom, only a single 1s orbital is needed, while for a carbon ...
Spartan Spectra & Properties Database (SSPD) – a set of about 252,000 molecules, with structures, energies, NMR and IR spectra, and wave functions calculated using the EDF2 [28] density functional theory with the 6-31G* basis set. [88] Spartan Molecular Database (SMD) – a set of about 100,000 molecules calculated from following models:
The Vienna Ab initio Simulation Package, better known as VASP, is a package written primarily in Fortran for performing ab initio quantum mechanical calculations using either Vanderbilt pseudopotentials, or the projector augmented wave method, and a plane wave basis set. [2]
The 2-dimensional Pople diagram describes the convergence of the quantum-mechanical nonrelativistic electronic energy with the size of the basis set and the level of electron correlation included in the wavefunction. [5] In order to reproduce accurate experimental thermochemical properties, secondary energetic contributions have to be considered.
The use of Gaussian orbitals in electronic structure theory (instead of the more physical Slater-type orbitals) was first proposed by Boys [2] in 1950. The principal reason for the use of Gaussian basis functions in molecular quantum chemical calculations is the 'Gaussian Product Theorem', which guarantees that the product of two GTOs centered on two different atoms is a finite sum of ...
The origin of the Hartree–Fock method dates back to the end of the 1920s, soon after the discovery of the Schrödinger equation in 1926. Douglas Hartree's methods were guided by some earlier, semi-empirical methods of the early 1920s (by E. Fues, R. B. Lindsay, and himself) set in the old quantum theory of Bohr.