Chirped modulation of molecular vibration in quinoidal thiophene after sub-5 fs excitation
Abstract
Fourier transformation of the real-time trace of sub-5 fs pump-induced molecular vibration in quinoidal thiophene in solution revealed coupled modes to the electronic excitation at 206, 447, and 1466 cm -1. Spectrogram analysis of 1466 cm -1 (C dbnd C stretching) mode showed that the amplitude and frequency of the mode are modulated with another low-frequency mode at about 220 cm -1, which is down chirped being induced by the coupling with modes of even lower frequency, resulting in the irreversible relaxation due to high mode density in the low-frequency range. This Letter thus reports on observation of the modulation of vibrational frequency with a chirped frequency.
- Publication:
-
Chemical Physics Letters
- Pub Date:
- October 2006
- DOI:
- 10.1016/j.cplett.2006.08.106
- Bibcode:
- 2006CPL...430...45W