Browsing by Author "Kobryanskii, Valerii M."

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The observation of strong dynamic electron-phonon couplings due to a breather state in trans-polyacetylene
(2009)
Teramoto, Takahiro
;
Wang, Zhuan
;
Kobryanskii, Valerii M.
;
Taneichi, Takashi
;
Kobayashi, Takayoshi
The dynamics preceding the separation process of a charged soliton pair after photoexcitation in trans-polyacetylene was successfully time-resolved using ultrafast spectroscopy with a few-optical-cycle laser. It was directly verified that after photoexcitation, the electron-hole pair relaxes with a breather mode as theory predicts with an electron-hole pair lifetime of 33-50 fs, which is in agreement with the electronic dephasing time. By applying the spectrogram analysis to the time trace of the absorbance change, the ultrafast amplitude and frequency modulations of C-C and C=C stretching modes lasting only shorter than 100 fs induced by breather modes can be observed simultaneously for the first time. The frequency shift of C-C and C=C stretching modes caused by the breather mode are observed in good agreement with the SSH Hamiltonian. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Ultrafast real-time vibronic coupling dynamics of a breather soliton in trans-polyacetylene with a few-optical-cycle-pulse laser
(2009-09-01)
Kobayashi, Takayoshi
;
Teramoto, Takahiro
;
Kobryanskii, Valerii M.
;
Taneichi, Takashi
;
電子物理學系
The dynamics preceding the spatial separation of a charged soliton pair after photoexcitation in trans-polyacetylene was successfully investigated by using ultrafast spectroscopy with a 6.2 fs pulse laser. It was directly verified that after photoexcitation, the electron-hole pair relaxes with a breather mode (i.e. multi-quanta vibronic states), as theory predicts, with an electron-hole pair lifetime of 33-50 fs. By applying spectrogram analysis to the time trace of the absorbance change, the ultrafast amplitude and frequency modulations of C-C and C=C stretching modes, induced by breathers and lasting no longer than 100 fs, can be observed Simultaneously for the first time. The frequency shifts of both modes were in good agreement with a simulation based on the Su-Schrieffer-Heeger model. It was found that the intensities of transition dipoles changed due to breathers, whereas transition energies were dominantly modulated by C=C stretching modes as recent theoretical work predicted. (C) 2009 Elsevier B.V. All rights reserved.
Ultrafast real-time vibronic coupling of a breather soliton in trans-polyacetylene using a few cycle pulse
(2009-01-01)
Kobayashi, Takayoshi
;
Teramoto, Takahiro
;
Kobryanskii, Valerii M.
;
Taneichi, Takashi
;
電子物理學系
The ultrafast electron-phonon coupling dynamics due to a breather soliton inducing amplitude and frequency modulations after photoexcitation in trans-polyacetylene was observed by ultrafast multicolor spectroscopy. The results were in good agreement with recent theoretical predictions. (C) 2009 Optical Society of America
Ultrafast real-time vibronic coupling of a breather soliton in trans-polyacetylene using a laser pulse with few cycles
(2009-01-01)
Teramoto, Takahiro
;
Wang, Zhuan
;
Kobryanskii, Valerii M.
;
Taneichi, Takashi
;
Kobayashi, Takayoshi
Simultaneous modulations of both frequencies and amplitudes of C-C and C=C stretching vibration modes, due to dynamical coupling to a breather soliton, in trans-polyacetylene was successfully time resolved. The frequency shifts of both modes were in good agreement with a simulation based on the Su-Schrieffer-Heeger model. It was found that the intensities of transition dipoles changed due to the breather, whereas transition energies were dominantly modulated by C=C stretching mode as recent theoretical work predicted.