Dynamical Behavior of a Ferroelectric Liquid Crystal with Monotropic Transition Temperatures during Electric-Field-Induced Switching Studied by Time-resolved Infrared Spectroscopy Combined with Singular Value Decomposition

2004 ◽  
Vol 43 (7A) ◽  
pp. 4294-4301
Author(s):  
Jinggang Zhao ◽  
Yukihiro Ozaki
1995 ◽  
Vol 49 (7) ◽  
pp. 977-980 ◽  
Author(s):  
Norihisa Katayama ◽  
Takashi Sato ◽  
Yukihiro Ozaki ◽  
Katsuyuki Murashiro ◽  
Makoto Kikuchi ◽  
...  

Pulsed electric-field-induced reorientation of a ferroelectric liquid crystal (FLC), 5-(2-fluorooctyloxy)-2-(4-hexylphenyl)-pyrimidine, has been investigated by using a dispersive submicrosecond time-resolved infrared spectroscopic technique. The observed absorbance decay for a band at 1440 cm−1 due to a ring-stretching mode of the phenylpyrimidine group indicates that the FLC molecule reorients from a stationary state with a slight delay (less than 1 μs) just after the upswing of the electric field, while counter-reorientation occurs with a delay time of a microsecond after the reverse of the electric field. The delay time for the counter-reorientation changes with temperature, indicating that the viscosity has a strong influence on the delay time. It is also indicated in the present study that the whole FLC molecule reorients simultaneously as a rigid rod in both the preliminary and the counter-reorientation process.


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.


2014 ◽  
Vol 369 (1647) ◽  
pp. 20130336 ◽  
Author(s):  
Kristoffer Haldrup

The development of new X-ray light sources, XFELs, with unprecedented time and brilliance characteristics has led to the availability of very large datasets with high time resolution and superior signal strength. The chaotic nature of the emission processes in such sources as well as entirely novel detector demands has also led to significant challenges in terms of data analysis. This paper describes a heuristic approach to datasets where spurious background contributions of a magnitude similar to (or larger) than the signal of interest prevents conventional analysis approaches. The method relies on singular-value decomposition of no-signal subsets of acquired datasets in combination with model inputs and appears generally applicable to time-resolved X-ray diffuse scattering experiments.


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