### Abstract

Discussion on wavelength dependent "anharmonic" effects in a pump-probe signal for a system of wavepacket on one- and two-dimensional harmonic potentials was given. The Fourier power spectrum of the signal, calculated for a model composed of a three-state electronic system coupled to a set of displaced harmonic oscillators, depends on the pulse duration. Condition under which the wavepacket motion in the harmonic potential substantially deviates from that of the classical point mass is derived. The Fourier power spectrum has enhanced components with frequencies of harmonics even in a system composed of ideally harmonic potentials. Utility of the Fourier analysis of the spectrum for clarification of the squeezed molecular vibrational state is discussed. Calculated oscillatory behavior in phase of a pump-probe signal, as a function of probe frequency, was discussed in terms of a two-dimensional effect on a pump-probe signal.

Original language | English |
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Pages (from-to) | 189-199 |

Number of pages | 11 |

Journal | Chemical Physics |

Volume | 341 |

Issue number | 1-3 |

DOIs | |

Publication status | Published - Nov 15 2007 |

Externally published | Yes |

### Keywords

- Fourier power spectrum
- Molecular dynamics
- Molecular vibration
- Phase
- Phonon
- Pump-probe spectroscopy
- Transient spectrum
- Ultra-fast phenomena
- Vibrational modes
- Wavepacket

### ASJC Scopus subject areas

- Physics and Astronomy(all)
- Physical and Theoretical Chemistry