Probe-Wavelength Dependence of Picosecond Time-Resolved Anti-Stokes Raman Spectrum of Canthaxanthin:  Determination of Energy States of Vibrationally Excited Molecules Generated via Internal Conversion from the Lowest Excited Singlet State

1997 ◽  
Vol 101 (19) ◽  
pp. 3494-3500 ◽  
Author(s):  
Takakazu Nakabayashi ◽  
Hiromi Okamoto ◽  
Mitsuo Tasumi
1996 ◽  
Vol 100 (2) ◽  
pp. 669-671 ◽  
Author(s):  
A. S. Jeevarajan ◽  
L. D. Kispert ◽  
N. I. Avdievich ◽  
M. D. E. Forbes

1999 ◽  
Vol 19 (1-4) ◽  
pp. 75-78 ◽  
Author(s):  
Takakazu Nakabayashi ◽  
Hiromi Okamoto ◽  
Mitsuo Tasumi

Vibrational relaxation dynamics of trans-stilbene in the S1 state immediately after photoexcitation is studied by picosecond time-resolved anti-Stokes Raman spectroscopy with several pump and probe wavelengths. Pump-wavelength dependence of the anti- Stokes spectrum indicates that, when pump photons with high excess energy (≈5200cm-1) are used, the anti-Stokes Raman bands at 0 ps delay time arise from vibrationally excited transients with excess vibrational energy not thermally distributed in the molecule. Probe-wavelength dependence suggests that the vibrationally excited transients at 0 ps are mostly on the lowest excited vibrational levels, as far as the olefinic C═C stretching and the C–Ph stretching modes are concerned. The vibrational relaxation process of S1trans-stilbene is discussed on the basis of the observed results.


1999 ◽  
Vol 19 (1-4) ◽  
pp. 329-333 ◽  
Author(s):  
K. Mohanalingam ◽  
S. Yamaguchi ◽  
H. Hamaguchi

We have measured the femtosecond time-resolved absorption spectra of para-nitroaniline in acetonitrile just after the photoexcitation to the lowest excited singlet state. The Singular Value Decomposition (SVD) analysis shows that two temporal evolutions follow the photoexcitation. The fast component (0.7 ps time constant) describes the dissociation of the 1:2 associated form to generate the 1:0 form followed by its reassociation with AN molecules. A slower temporal evolution of 10 ps is most likely to represent the cooling down process of the whole system.


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