### Resumé

We present a new implementation of the second-order polarization propagator approximation (SOPPA) using a direct linear transformation approach, in which the SOPPA equations are solved iteratively. This approach has two important advantages over its predecessors. First, the direct linear transformation allows for more efficient calculations for large two particle-two hole excitation manifolds. Second, the operation count for SOPPA is lowered by one order, to N^{5}. As an application of the new implementation, we calculate the excitation energies and oscillator strengths of the lowest singlet and triplet transitions for benzene and naphthalene. The results compare well with experiment and CASPT2 values, calculated with identical basis sets and molecular geometries. This indicates that SOPPA can provide reliable values for excitation energies and response properties for relatively large molecular systems.

Originalsprog | Engelsk |
---|---|

Tidsskrift | Journal of Chemical Physics |

Vol/bind | 105 |

Udgave nummer | 14 |

Sider (fra-til) | 5886-5900 |

Antal sider | 15 |

ISSN | 0021-9606 |

Status | Udgivet - 1996 |

### Fingeraftryk

### Citer dette

*Journal of Chemical Physics*,

*105*(14), 5886-5900.

}

*Journal of Chemical Physics*, bind 105, nr. 14, s. 5886-5900.

**A new implementation of the second-order polarization propagator approximation (SOPPA) : The excitation spectra of benzene and naphthalene.** / Packer, Martin J.; Dalskov, Erik K.; Enevoldsen, Thomas; Jensen, Hans Jörgen Aa; Oddershede, Jens.

Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review

TY - JOUR

T1 - A new implementation of the second-order polarization propagator approximation (SOPPA)

T2 - The excitation spectra of benzene and naphthalene

AU - Packer, Martin J.

AU - Dalskov, Erik K.

AU - Enevoldsen, Thomas

AU - Jensen, Hans Jörgen Aa

AU - Oddershede, Jens

PY - 1996

Y1 - 1996

N2 - We present a new implementation of the second-order polarization propagator approximation (SOPPA) using a direct linear transformation approach, in which the SOPPA equations are solved iteratively. This approach has two important advantages over its predecessors. First, the direct linear transformation allows for more efficient calculations for large two particle-two hole excitation manifolds. Second, the operation count for SOPPA is lowered by one order, to N5. As an application of the new implementation, we calculate the excitation energies and oscillator strengths of the lowest singlet and triplet transitions for benzene and naphthalene. The results compare well with experiment and CASPT2 values, calculated with identical basis sets and molecular geometries. This indicates that SOPPA can provide reliable values for excitation energies and response properties for relatively large molecular systems.

AB - We present a new implementation of the second-order polarization propagator approximation (SOPPA) using a direct linear transformation approach, in which the SOPPA equations are solved iteratively. This approach has two important advantages over its predecessors. First, the direct linear transformation allows for more efficient calculations for large two particle-two hole excitation manifolds. Second, the operation count for SOPPA is lowered by one order, to N5. As an application of the new implementation, we calculate the excitation energies and oscillator strengths of the lowest singlet and triplet transitions for benzene and naphthalene. The results compare well with experiment and CASPT2 values, calculated with identical basis sets and molecular geometries. This indicates that SOPPA can provide reliable values for excitation energies and response properties for relatively large molecular systems.

UR - http://www.scopus.com/inward/record.url?scp=0000357189&partnerID=8YFLogxK

M3 - Journal article

AN - SCOPUS:0000357189

VL - 105

SP - 5886

EP - 5900

JO - The Journal of Chemical Physics

JF - The Journal of Chemical Physics

SN - 0021-9606

IS - 14

ER -