scholarly journals Low-frequency collective vibrational modes of asparagine by terahertz time-domain spectroscopy

2006 ◽  
Vol 55 (8) ◽  
pp. 4091
Author(s):  
Ma Shi-Hua ◽  
Shi Yu-Lei ◽  
Xu Xin-Long ◽  
Yan Wei ◽  
Yang Yu-Ping ◽  
...  
Keyword(s):  
Time Domain ◽  
Low Frequency ◽  
Vibrational Modes ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Collective Vibrational Modes

Narrow-Line Waveguide Terahertz Time-Domain Spectroscopy of Aspirin and Aspirin Precursors

2008 ◽  
Vol 62 (3) ◽  
pp. 319-326 ◽  
Author(s):  
N. Laman ◽  
S. Sree Harsha ◽  
D. Grischkowsky
Keyword(s):  
Salicylic Acid ◽  
Time Domain ◽  
Low Frequency ◽  
Far Infrared ◽  
Metal Plate ◽  
Thz Radiation ◽  
Vibrational Modes ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Parallel Plate Waveguide

Low frequency vibrational modes of pharmaceutical molecules are dependent on the molecule as a whole and can be used for identification purposes. However, conventional Fourier transform far-infrared spectroscopy (FT-IR) and terahertz time-domain spectroscopy (THz-TDS) often result in broad, overlapping features that are difficult to distinguish. The technique of waveguide THz-TDS has been recently developed, resulting in sharper spectral features. Waveguide THz-TDS consists of forming an ordered polycrystalline film on a metal plate and incorporating that plate in a parallel-plate waveguide, where the film is probed by THz radiation. The planar order of the film on the metal surface strongly reduces the inhomogeneous broadening, while cooling the waveguide to 77 K reduces the homogeneous broadening. This combination results in sharper absorption lines associated with the vibrational modes of the molecule. Here, this technique has been demonstrated with aspirin and its precursors, benzoic acid and salicylic acid, as well as the salicylic acid isomers 3- and 4-hydroxybenzoic acid. Linewidths as narrow as 20 GHz have been observed, rivaling single crystal measurements.

scholarly journals Low-frequency optical phonon modes and carrier mobility in the halide perovskite CH3NH3PbBr3 using terahertz time-domain spectroscopy

2017 ◽  
Vol 111 (20) ◽  
pp. 201903 ◽  
Author(s):  
Daming Zhao ◽  
Jonathan M. Skelton ◽  
Hongwei Hu ◽  
Chan La-o-vorakiat ◽  
Jian-Xin Zhu ◽  
...  
Keyword(s):  
Time Domain ◽  
Optical Phonon ◽  
Carrier Mobility ◽  
Low Frequency ◽  
Terahertz Time Domain Spectroscopy ◽  
Phonon Modes ◽  
Time Domain Spectroscopy ◽  
Halide Perovskite

Low-frequency dynamics of bacteriorhodopsin studied by terahertz time-domain spectroscopy

2010 ◽  
Vol 12 (35) ◽  
pp. 10255 ◽  
Author(s):  
Shintaro Kawaguchi ◽  
Ohki Kambara ◽  
Mikihiro Shibata ◽  
Hideki Kandori ◽  
Keisuke Tominaga
Keyword(s):  
Time Domain ◽  
Low Frequency ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy

scholarly journals Terahertz Time-Domain Spectroscopy and Low-Frequency Raman Scattering of Crystalline and Glassy Pharmaceutical Indapamide

2015 ◽  
Vol 46 ◽  
pp. 16-22 ◽  
Author(s):  
Yukiko Kobayashi ◽  
Tomohiko Shibata ◽  
Tatsuya Mori ◽  
Seiji Kojima
Keyword(s):  
Raman Scattering ◽  
Raman Spectra ◽  
Imaginary Part ◽  
Time Domain ◽  
Low Frequency ◽  
Dielectric Constants ◽  
Coupling Constants ◽  
Exclusion Principle ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy

We performed terahertz time-domain spectroscopy and low-frequency Raman scattering on crystalline and glassy states of pharmaceutical indapamide (IND). We have determined the real and imaginary part of the complex dielectric constants and the imaginary part of the Raman susceptibility in the THz region. Several phonon peaks have been observed in the crystalline IND and the mutual exclusion principle of infrared and Raman spectroscopy holds in the measured frequency range. In a glassy state of IND, a broad absorption peak has been observed in both the THz and the Raman spectra with different spectral shape, and this disagreement indicates that the far-infrared and Raman light-vibration coupling constants are different in the glassy IND. A clear boson peak has been observed in the Raman spectra of the glassy IND at about 0.5 THz.

Characteristic fingerprint spectrum of neurotransmitter norepinephrine with broadband terahertz time-domain spectroscopy

The Analyst ◽  
2019 ◽  
Vol 144 (8) ◽  
pp. 2504-2510 ◽  
Author(s):  
Zhongjie Zhu ◽  
Chao Cheng ◽  
Chao Chang ◽  
Guanhua Ren ◽  
Jianbing Zhang ◽  
...  
Keyword(s):  
Absorption Spectrum ◽  
Time Domain ◽  
Vibrational Modes ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Thz Absorption ◽  
Broadband Terahertz

A broadband THz absorption spectrum of NE corresponds to specific vibrational modes.

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