Broadband terahertz time-domain spectroscopic study on form II polyvinylidene fluoride

Mori, Tatsuya; Igawa, Hikaru; Okada, Daichi; Yamamoto, Yohei; Iwamoto, Kaoru; Toyota, Naoki; Kojima, Seiji

doi:10.1016/j.molstruc.2014.12.004

Cited by 9 publications

(15 citation statements)

References 17 publications

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“…In the analysis of THz-TDS spectra, the observed spectra of two THz-TDS systems are combined to cover a broad THz region [1,11]. The low frequency sides of THz transmission spectra were measured in the frequency range from 0.1 to 3.0 THz using a standard THz-TDS equipment (RT-10000, Tochigi Nikon Co.) with low temperature-grown GaAs photoconductive antennas for both the emitter and detector.…”

Section: Experimental and Calculation Methodsmentioning

confidence: 99%

“…The low frequency sides of THz transmission spectra were measured in the frequency range from 0.1 to 3.0 THz using a standard THz-TDS equipment (RT-10000, Tochigi Nikon Co.) with low temperature-grown GaAs photoconductive antennas for both the emitter and detector. The photoconductive antennas were triggered by a mode-locked Ti:sapphire pulsed laser with a wave-length of 780 nm, a pulse width of less than 100 fs, and a repetition rate of 80 MHz [1,11]. The high frequency sides of THz transmission spectra were measured in the frequency range from 1.0 to 5.0 THz using an recently developed THz-TDS equipment (TAS7500SU, ADVANTEST Co.) with a Cherenkov type THz generator and the high speed AOS technique [1,11].…”

Section: Experimental and Calculation Methodsmentioning

confidence: 99%

“…The photoconductive antennas were triggered by a mode-locked Ti:sapphire pulsed laser with a wave-length of 780 nm, a pulse width of less than 100 fs, and a repetition rate of 80 MHz [1,11]. The high frequency sides of THz transmission spectra were measured in the frequency range from 1.0 to 5.0 THz using an recently developed THz-TDS equipment (TAS7500SU, ADVANTEST Co.) with a Cherenkov type THz generator and the high speed AOS technique [1,11]. Since the difference in the spectra observed by these systems was at most 5%, we smoothly connected the absolute value of the complex dielectric constants of the samples by multiplying a factor in the data analysis.…”

Section: Experimental and Calculation Methodsmentioning

confidence: 99%

“…The THz dynamics have been intently investigated for various kinds of materials such as polymers [1], pharmaceuticals [2], ferroelectrics [3], and so on. Furthermore, there has been the significant improvement of the methods for measuring not only the crystalline state, but also the amorphous and liquid states of materials.…”

Section: Introductionmentioning

confidence: 99%

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Broadband Terahertz Time-Domain Spectroscopy and Low-Frequency Raman Scattering of Propylene Glycol

Koda

Mori

Kojima

2015

ILCPA

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Abstract. Two different THz-TDS systems were used for the accurate study of broadband terahertz dynamics between 0.1 and 5.0 THz. These systems enabled to observe the whole spectral structure of the broad peak at 1.5 THz in propylene glycol. At high-frequency side of the broad peak in the dielectric spectrum, the small shoulder peak at 3.6 THz was also observed. It is assigned to the inter-molecular vibration, which is supported by the precedent report and the Gaussian calculation. In contrast, the low-frequency side of the broad peak includes the contribution of the relaxation processes which exist in the MHz and GHz region. Furthermore, we compared the dielectric spectrum with the Raman spectrum and concluded that the mode at 3.6 THz is IR active while Raman inactive.

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Section: Experimental and Calculation Methodsmentioning

confidence: 99%

Section: Experimental and Calculation Methodsmentioning

confidence: 99%

Section: Experimental and Calculation Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Broadband Terahertz Time-Domain Spectroscopy and Low-Frequency Raman Scattering of Propylene Glycol

Koda

Mori

Kojima

2015

ILCPA

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“…Recent researchers have regarded the BP as the broad peak appearing in the imaginary part of the complex dielectric constant ε (ν) in the THz region [44][45][46], although the name of the broad peak has recently been changed to the "VDOS peak" [47]. In order to understand how the BP appears in the IR spectra, we must consider the following relation derived from the linear response theory for disordered materials [48]:…”

Section: Introductionmentioning

confidence: 99%

Boson peak dynamics of glassy glucose studied by integrated terahertz-band spectroscopy

et al. 2016

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We performed terahertz time-domain spectroscopy, low-frequency Raman scattering, and Brillouin light scattering on vitreous glucose to investigate the boson peak (BP) dynamics. In the spectra of α(ν)/ν 2 [α(ν) is the absorption coefficient], the BP is clearly observed around 1.1 THz. Correspondingly, the complex dielectric constant spectra show a universal resonancelike behavior only below the BP frequency. As an analytical scheme, we propose the relative light-vibration coupling coefficient (RCC), which is obtainable from the combination of the far-infrared and Raman spectra. The RCC reveals that the infrared light-vibration coupling coefficient C IR (ν) of the vitreous glucose behaves linearly on frequency which deviates from Taraskin

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A Study of the Terahertz Spectra of Crystalline Materials (Polyethylene, Poly(Vinylidene Fluoride) form II, and α-D-Glucose) Using NDDO Semiempirical Methods

Chamorro‐Posada

2018

J Appl Spectrosc

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Semi-empirical quantum chemistry methods offer a very interesting compromise between accuracy and computational load. In order to assess the performance of NDDO methods in the interpretation of terahertz spectra, the low frequency vibration modes of three crystalline materials, namely, polyethylene, poly(vinylidene fluoride) form II and α-D-glucose have been studied using the PM6 and PM7 Hamiltonians and the results have been compared with the experimental data and former calculations. The results show good qualitative or semi-quantitative agreement with the experimentally observed terahertz spectra. arXiv:1604.03919v1 [physics.chem-ph] 13 Apr 2016 to permit the identification of the transition from a 2D form to a 3D arrangement in a carbon nitride polymer [3]. The absorption in the THz has been demonstrated to display a direct correlation with the stacking order along the c axis in different types of carbon materials [4].The complexity of the underlying physical effects affecting the observed attenuation, with contributions from intra-and inter-molecular modes and a strong impact of disorder, hinders the interpretation of the data. Theoretical methods are essential for this task, and the versatility of computational quantum chemistry methods is particularly attractive for the discernment of THz spectra.The theoretical prediction of the terahertz spectra of crystalline materials has been based mostly on force-field or density functional theory (DFT) methods [1]. Ab-initio and density functional theory (DFT) methods are regarded as highly accurate in the prediction of molecular vibrations [5] when used with correction factors to compensate systematic deviations. Nevertheless, the relevance of long-range and intermolecular contributions can make the study of the THz vibrational spectra of materials very demanding in terms of the required solid-state calculations over large systems. This imposes a severe limitation in the use of computationally costly ab-initio or DFT methods. On the other hand, semi-empirical methods [6,7], specially with the recently developed parallel implementations for shared-memory multiprocessor and massively-parallel graphics processing units architectures [8], permit to study the vibrations in large molecular systems and crystals at reduced computation times.Semi-empirical NDDO (neglect of the diatomic differential overlap) computations are based on approximations and data obtained from given training sets which calls for their assessment when employed in a given task, and can be placed at an intermediate theory level between force-field and ab-initio or DFT methods. Poor performance of the AM1 [9] and the PM3 [10] methods reported in [6] disfavored their use in the analysis of vibrational spectra until the appearance of the PM6 parametrization [11], with improved accuracy in the prediction of geometries and the description of the material vibrations [7]. The recently developed PM7 [12] method yields higher accuracy in the guessed structures, particularly for large molecular crystals, even ...

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Broadband terahertz time-domain spectroscopic study on form II polyvinylidene fluoride

Cited by 9 publications

References 17 publications

Broadband Terahertz Time-Domain Spectroscopy and Low-Frequency Raman Scattering of Propylene Glycol

Broadband Terahertz Time-Domain Spectroscopy and Low-Frequency Raman Scattering of Propylene Glycol

Boson peak dynamics of glassy glucose studied by integrated terahertz-band spectroscopy

A Study of the Terahertz Spectra of Crystalline Materials (Polyethylene, Poly(Vinylidene Fluoride) form II, and α-D-Glucose) Using NDDO Semiempirical Methods

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