### Abstract

The lowest photoexcited triplet state of thiophene oligomers (nT) with n = 2 - 8 has been investigated by pulsed EPR spectroscopy. The characteristic EPR lineshape is analyzed by performing spectral simulations. The determined D values decrease with increasing chain length showing a linear dependence on the inverse chain length. Furthermore conformational effects have been observed. We compare the results with theoretical calculations of the zero-field splitting parameters. The calculations are based on a semiempirical 'one electron per site' model including electron-electron interactions. The computed D values are in excellent agreement with the EPR data. The chain length dependence of D could be rationalized by computing electron spin densities and bond length distortions, which clearly indicate that the triplet excitation reaches a finite extention over about four thiophene rings.

Original language | English |
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Pages (from-to) | 607-608 |

Number of pages | 2 |

Journal | Synthetic Metals |

Volume | 84 |

Issue number | 1-3 |

Publication status | Published - Jan 1 1997 |

### Keywords

- Electron spin resonance
- Excited states
- Oligothiophenes

### ASJC Scopus subject areas

- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry

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## Cite this

*Synthetic Metals*,

*84*(1-3), 607-608.