### Abstract

New types of bond function (BF) basis sets are proposed and tested for quantum chemical applications. First, BF basis sets constituted of conventional Gaussian-type orbitals (GTO) are considered. Both the exponents and the positions of the BFs are optimized, but, in contrast to previous studies, the position of each BF shell is varied separately. Second, new types of basis functions, the general ellipsoidal Gaussian-type orbitals (EGTOs), are proposed for quantum chemical applications. The EGTOs are distorted spherical GTOs and, as such, are expected to be well suited for describing the polarized charge densities in molecular environments. EGTOs can be used either as atom-centered (AC) basis functions or as BFs. In this study, the latter possibility is explored, and BF basis sets including EGTOs are optimized and compared to those containing only conventional GTO BFs. The performance of the developed GTO and EGTO BF basis sets is assessed for Hartree–Fock and density functional calculations against conventional AC GTO basis sets. Our results show that using GTO BF basis sets, the results are significantly improved, while the number of the basis functions can be decreased by about 10 %, which is not dramatic; however, the average angular momentum quantum number in the BF sets is significantly lower. The accuracy of the computed energies can be further increased by about 15 % if EGTO BFs are used.

Original language | English |
---|---|

Journal | Theoretical Chemistry Accounts |

Volume | 134 |

Issue number | 6 |

DOIs | |

Publication status | Published - Jun 16 2015 |

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### Keywords

- Bond functions
- Ellipsoidal Gaussian functions
- Polarization functions
- Unconventional basis functions

### ASJC Scopus subject areas

- Physical and Theoretical Chemistry

### Cite this

*Theoretical Chemistry Accounts*,

*134*(6). https://doi.org/10.1007/s00214-015-1670-2

**Unconventional bond functions for quantum chemical calculations.** / Mester, Dávid; Csontos, József; Kállay, M.

Research output: Contribution to journal › Article

*Theoretical Chemistry Accounts*, vol. 134, no. 6. https://doi.org/10.1007/s00214-015-1670-2

}

TY - JOUR

T1 - Unconventional bond functions for quantum chemical calculations

AU - Mester, Dávid

AU - Csontos, József

AU - Kállay, M.

PY - 2015/6/16

Y1 - 2015/6/16

N2 - New types of bond function (BF) basis sets are proposed and tested for quantum chemical applications. First, BF basis sets constituted of conventional Gaussian-type orbitals (GTO) are considered. Both the exponents and the positions of the BFs are optimized, but, in contrast to previous studies, the position of each BF shell is varied separately. Second, new types of basis functions, the general ellipsoidal Gaussian-type orbitals (EGTOs), are proposed for quantum chemical applications. The EGTOs are distorted spherical GTOs and, as such, are expected to be well suited for describing the polarized charge densities in molecular environments. EGTOs can be used either as atom-centered (AC) basis functions or as BFs. In this study, the latter possibility is explored, and BF basis sets including EGTOs are optimized and compared to those containing only conventional GTO BFs. The performance of the developed GTO and EGTO BF basis sets is assessed for Hartree–Fock and density functional calculations against conventional AC GTO basis sets. Our results show that using GTO BF basis sets, the results are significantly improved, while the number of the basis functions can be decreased by about 10 %, which is not dramatic; however, the average angular momentum quantum number in the BF sets is significantly lower. The accuracy of the computed energies can be further increased by about 15 % if EGTO BFs are used.

AB - New types of bond function (BF) basis sets are proposed and tested for quantum chemical applications. First, BF basis sets constituted of conventional Gaussian-type orbitals (GTO) are considered. Both the exponents and the positions of the BFs are optimized, but, in contrast to previous studies, the position of each BF shell is varied separately. Second, new types of basis functions, the general ellipsoidal Gaussian-type orbitals (EGTOs), are proposed for quantum chemical applications. The EGTOs are distorted spherical GTOs and, as such, are expected to be well suited for describing the polarized charge densities in molecular environments. EGTOs can be used either as atom-centered (AC) basis functions or as BFs. In this study, the latter possibility is explored, and BF basis sets including EGTOs are optimized and compared to those containing only conventional GTO BFs. The performance of the developed GTO and EGTO BF basis sets is assessed for Hartree–Fock and density functional calculations against conventional AC GTO basis sets. Our results show that using GTO BF basis sets, the results are significantly improved, while the number of the basis functions can be decreased by about 10 %, which is not dramatic; however, the average angular momentum quantum number in the BF sets is significantly lower. The accuracy of the computed energies can be further increased by about 15 % if EGTO BFs are used.

KW - Bond functions

KW - Ellipsoidal Gaussian functions

KW - Polarization functions

KW - Unconventional basis functions

UR - http://www.scopus.com/inward/record.url?scp=84929192789&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84929192789&partnerID=8YFLogxK

U2 - 10.1007/s00214-015-1670-2

DO - 10.1007/s00214-015-1670-2

M3 - Article

AN - SCOPUS:84929192789

VL - 134

JO - Theoretical Chemistry Accounts

JF - Theoretical Chemistry Accounts

SN - 1432-881X

IS - 6

ER -