A Multireference Coupled-Cluster Study of Electronic Excitations in Furan and Pyrrole†
| Autor: | Josef Paldus, Xiangzhu Li |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Chemistry
Electrons Configuration interaction symbols.namesake Coupled cluster Excited state Cluster (physics) Rydberg formula symbols Quantum Theory Computer Simulation Pyrroles Physics::Chemical Physics Physical and Theoretical Chemistry Atomic physics Perturbation theory Furans Excitation Basis set |
| Zdroj: | The Journal of Physical Chemistry A. 114:8591-8600 |
| ISSN: | 1520-5215 1089-5639 |
| DOI: | 10.1021/jp911602k |
| Popis: | A multireference (MR), general-model-space (GMS), state-universal (SU), coupled-cluster (CC) method that considers singly (S) and doubly (D) excited cluster amplitudes relative to the reference configurations spanning the model space (GMS SU CCSD) is employed to investigate a number of low-lying excited states of two five-membered, six pi -electron aromatic ring molecules, namely, furan and pyrrole. An extended basis set that includes diffuse functions and molecule-centered Rydberg functions is employed. Computed vertical excitation energies are compared with experimental values as well as with other theoretical results, namely, those obtained by the equation-of-motion (EOM) CCSD method or, equivalently, the symmetry adapted cluster configuration interaction (SAC-CI) method, by the MR CI method, by MR perturbation theory, and by other methods whenever available. For excited states dominated by single-excitations the GMS SU CCSD energies represent an improvement relative to the most closely related EOM CCSD results by about 0.1 eV. |
| Databáze: | OpenAIRE |
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