## Abstract

Non-covalent interactions can usually be described accurately at the coupled-cluster level of theory using single, double and triple excitations, the latter within a perturbation-theory framework. However, since the computations with the corresponding coupled-cluster model, CCSD(T), are computationally very demanding, they can often not be carried out in large enough basis sets. This leads to a basis-set truncation error. To correct this error, a basis-set correction can be computed at the level of second-order Møller-Plesset (MP2) perturbation theory in the limit of a complete basis set, but such a correction tends to overestimate the magnitude of the basis-set truncation error. In the present work, we suggest to damp the basis-set correction obtained at the complete-basis-set MP2 level using interference factors for individual occupied orbital pairs. The approach is applied to the non-covalent interactions of the S22B database, where the interference correction turns out to be very small.

Original language | English (US) |
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Pages (from-to) | 2299-2305 |

Number of pages | 7 |

Journal | Molecular Physics |

Volume | 111 |

Issue number | 14-15 |

DOIs | |

State | Published - 2013 |

### Bibliographical note

Funding Information:This research has been supported by the Deutsche Forschungs-gemeinschaft through the Center for Functional Nanostructures (CFN, Project No. C3.3).

## Keywords

- Coupled-cluster theory
- Explicit correlation
- Interference factors
- Non-covalent interactions
- S22 test set