### Résumé

An analytical method was elaborated to compute the second derivative of the Hartree-Fock energy with respect to the unit cell length (Ỹ) in stereoregular polymers. The evaluation of Ỹ was performed in a single-shot calculation once the optimal geometry is known. The formulas necessary to calculate cell and mixed Hessians of individual one- and two-electron integrals were implemented efficiently. A seven-step CPHF procedure was used to obtain the derivatives of the density matrix in a fashion consistent with the SCF procedure. Using an adapted long-range effects scheme and efficient quadrature methods for transforming k-space density matrix and its derivatives into their real-space counterparts, an accuracy of 10^{-9} a.u. was obtained on the final Hessian elements.

langue originale | Anglais |
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Pages (de - à) | 373-388 |

Nombre de pages | 16 |

journal | The journal of chemical physics |

Volume | 118 |

Numéro de publication | 1 |

Les DOIs | |

Etat de la publication | Publié - 1 janv. 2003 |

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## Contient cette citation

*The journal of chemical physics*,

*118*(1), 373-388. https://doi.org/10.1063/1.1523909