### Abstract

Good, density functional quality (B3LYP/6-31G*) ground state total electronic energies have been approximated using single point Hartree-Fock-self consistent field (HF-SCF/6-31G*) total energies and Mulliken partial charges versus. Mulliken matrix (electrons assigned to atoms and atoms pairs from Mulliken population analysis). This is a development of our rapid estimation of basis set error and correlation energy from partial charges (REBECEP) method, published earlier (see references [21,22,30]). The development is as follows: (1) A larger set of atoms (H, C, N, O, F, Si, P and S) are considered as building blocks for closed shell, neutral, ground state molecules at their equlibrium geometry; (2) geometries near equilibrium geometry are also considered; (3) A larger set, containing 115 molecules, was used to fit REBECEP parameters; (4) most importantly, electrons belonging to chemical bonds (between atom pairs) are also considered (Mulliken matrix) in addition to the atoms (Mulliken charges), using more REBECEP parameters to fit and yielding a more flexible algorithm. With these parameters a rather accurate closed shell ground state electronic total energy can be obtained from a small basis set HF-SCF calculation in the vicinity of optimal geometry. The 3.3 kcal/mol root mean square deviation of REBECEP improves to 1.5 kcal/mol when using Mulliken matrix instead of Mulliken charges.

Original language | English |
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Pages (from-to) | 298-307 |

Number of pages | 10 |

Journal | Theoretical Chemistry Accounts |

Volume | 115 |

Issue number | 4 |

DOIs | |

Publication status | Published - Apr 1 2006 |

### Keywords

- Ab initio total ground state electronic energy
- Basis set error
- Correlation energy
- Density functional theory
- Mulliken partial charge

### ASJC Scopus subject areas

- Physical and Theoretical Chemistry