### Abstract

The internal rotational barrier heights of biphenyl were calculated with the Dunning correlation consisted basis sets (up to cc-pVQZ, 960 basis functions) and the electron correlation correction by the second order Møller-Plesset method (MP2). Although previous Hartree-Fock (HF) and MP2 calculations showed that the internal rotational barrier height at 0° (ΔE_{0}) was substantially larger than that at 90° (ΔE_{90}), our MP2/cc-pVQZ//MP2/6-31G* calculations showed that ΔE_{0} (2.28 kcal/mol) was close to ΔE_{90} (2.13 kcal/mol), which agreed with the estimation from experimental measurements. The calculations of benzene dimers suggested that the dispersion interaction increased the relative stability of the coplanar conformer. The basis sets employed in the previous calculations were not large enough to evaluate the attractive dispersion interaction. The underestimation of the stabilization of the coplanar conformer by the dispersion interaction would be one of the reasons for the overestimation of ΔE_{0} in the previous calculations.

Original language | English |
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Pages (from-to) | 2858-2861 |

Number of pages | 4 |

Journal | Journal of Chemical Physics |

Volume | 110 |

Issue number | 2-12 |

Publication status | Published - 1999 Feb 8 |

Externally published | Yes |

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### ASJC Scopus subject areas

- Atomic and Molecular Physics, and Optics

### Cite this

*Journal of Chemical Physics*,

*110*(2-12), 2858-2861.