標題: Vibrational Energy Flow between Modes by Dynamic Mode Coupling in THIATS J-Aggregates
作者: Hasegawa, Daisuke
Nakata, Kazuaki
Tokunaga, Eiji
Okamura, Kotaro
Du, Juan
Kobayashi, Takayoshi
電子物理學系
Department of Electrophysics
公開日期: 14-Nov-2013
摘要: We performed ultrafast pump-probe spectroscopy of J-aggregates of 3,3'-disulfopropyl-5,5'-dichloro-9-ethyl thiacarbocyanine triethylammonium (THIATS), one of the most typical cyanine dyes, and detected excited molecular vibrations, using a sub-10 fs pulse laser. The time-resolved two-dimensional difference absorption (Delta A) spectra are observed between -314 and 1267 fs. By performing the Fourier transform and spectrogram analysis, vibrational modes in THIATS are observed at 285, 485, 555, 824, and 1633 cm(-1) and there was a modulation of the vibrational frequencies around 1633 cm(-1) which depend on the delay time, respectively. By the analysis of the modulation, energy flow is found to take place from other modes to the 1633 cm(-1) mode through the low frequency mode with similar to 50 cm(-1). Also, by fitting the real-time traces of Delta A with the sum of two exponential functions and a constant term, the average lifetimes of three electronically excited states were found to be tau(1) = 52 +/- 5 fs and tau(2) = 540 +/- 78 fs. By performing single-exponential fitting around the stationary absorption peak at 1.990 eV, in the negative time range, the electronic dephasing time, T-2(ele), is determined to be 18.30 fs.
URI: http://dx.doi.org/10.1021/jp4015228
http://hdl.handle.net/11536/23263
ISSN: 1089-5639
DOI: 10.1021/jp4015228
期刊: JOURNAL OF PHYSICAL CHEMISTRY A
Volume: 117
Issue: 45
起始頁: 11441
結束頁: 11448
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