scholarly journals Temperature and Pressure Effects on Terahertz Time-Domain Spectroscopy of Crystalline Methedrine by Molecular Dynamics Simulation

2014 ◽  
Vol 04 (04) ◽  
pp. 58-69 ◽  
Author(s):  
Yu Xin ◽  
Hassan Yousefi Oderji ◽  
Ran Hai ◽  
Cailong Fu ◽  
Raja Aljarmouzi ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Time Domain ◽  
Pressure Effects ◽  
Dynamics Simulation ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Temperature And Pressure ◽  
Temperature And Pressure Effects

Molecular Dynamics Simulation on Terahertz Spectra of Methamphetamine Hydrochloride

2013 ◽  
Vol 760-762 ◽  
pp. 35-39 ◽  
Author(s):  
Yu Xin ◽  
Hassan Yousefi Oderji ◽  
Ran Hai ◽  
Hong Bin Ding
Keyword(s):  
Molecular Dynamics ◽  
Dipole Moment ◽  
Time Domain ◽  
Dynamics Simulation ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Trade Name ◽  
Experimental Spectroscopy ◽  
The Fourier Transform ◽  
Dynamics Simulations

Methamphetamine hydrochloride crystal (trade name Methedrine) that is one of the illegal drugs used as a stimulant to the nervous system has been considered to be detected by T-ray via the terahertz time-domain spectroscopy (THz-TDS). In this research, we simulated the THz spectra of Methedrine by molecular dynamics methods for the first time. The terahertz spectra at temperatures 78.4K, 200K, 294K and 400K in the frequency range of 10-100cm-1 were investigated, which exhibited the variation of spectra position and intensity with increasing temperature. Firstly, we used DL_POLY simulation package to obtain the instantaneous values of the dipole moment. Subsequently, the intensities of THz vibrational modes were obtained by the Fourier transform of the autocorrelation function of the dipole moment. The results showed our theoretical calculation by molecular dynamics simulations got a good consistency with available experimental spectroscopy. These are useful to determine the best conditions of temperature at which the terahertz time-domain spectroscopy of Methedrine results a highly informative spectrum.

Molecular Dynamics Simulation of Recoil Nucleus Displacement Cascade in Zircon

1998 ◽  
Vol 540 ◽  
Author(s):  
Jean-Paul Crocombette ◽  
Dominique Ghaleb
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Molecular Simulations ◽  
Recoil Nucleus ◽  
Dynamics Simulation ◽  
Local Temperature ◽  
Displacement Cascades ◽  
Displacement Cascade ◽  
Temperature And Pressure

AbstractThe results of molecular simulations of a-recoil nucleus displacement cascades in zircon (ZrSiO4) are presented. The local temperature and pressure are found to increase dramatically during the cascade. The structure of the cascade tracks is amorphous. Its shape has been analyzed in terms of disordered and distorted cations. SiO2 nanophase are found to exist in the tracks consistently with what is observed in the experiments.

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