Terahertz Time Domain Spectroscopy and Density Functional Theory Calculations of Peptides

Author(s):  
Jens Neu ◽  
Charles A. Schmuttenmaer
2012 ◽  
Vol 441 ◽  
pp. 741-745
Author(s):  
Si Chen ◽  
Chao Yan ◽  
Bin Luo ◽  
Bin Yang

P-chloroaniline is one of the most important azo dye intermediates. It is a highly desired research on the identification of P-chloroaniline. Terahertz time domain spectroscopy (THz-TDS) is sensitive to the molecule structure of compound. In this paper, the spectra of P-chloroaniline located at the region from 0.1 to 3 THz were tested by THz-TDS system, and then the geometry structure of p-chloroaniline at the range of 0 THz to 10 THz was optimized, resonance frequency was calculated by Gussian03 software based on the density functional theory (DFT). The results showed that the absorbance peaks at 1.96 THz and 2.20 THz were caused by the hydrogen bonding force or crystal phonon mode, and suggested that it is feasible to identify P-chloroaniline by THz-TDS, which is of great value to the examination of banned azo dyes in the future.


RSC Advances ◽  
2021 ◽  
Vol 11 (46) ◽  
pp. 28898-28907
Author(s):  
Xiaoxue Du ◽  
Yafei Wang ◽  
Xiaodong Zhang ◽  
Guoxin Ma ◽  
Yong Liu ◽  
...  

Terahertz technology is receiving increasing attention for its use as an efficient non-destructive, non-contact and label-free optical method for qualitative and quantitative detection.


2011 ◽  
Vol 9 (s1) ◽  
pp. s10506-310508
Author(s):  
Zhuanping Zheng Zhuanping Zheng ◽  
Wenhui Fan Wenhui Fan ◽  
Bing Xue Bing Xue

2006 ◽  
Vol 71 (11-12) ◽  
pp. 1525-1531 ◽  
Author(s):  
Wojciech Grochala

The enthalpy of four polymorphs of CaN has been scrutinized at 0 and 100 GPa using density functional theory calculations. It is shown that structures of diamagnetic calcium diazenide (Ca2N2) are preferred over the cubic ferromagnetic polymorph (CaN) postulated before, both at 0 and 100 GPa.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Chih-Chuen Lin ◽  
Phani Motamarri ◽  
Vikram Gavini

AbstractWe present a tensor-structured algorithm for efficient large-scale density functional theory (DFT) calculations by constructing a Tucker tensor basis that is adapted to the Kohn–Sham Hamiltonian and localized in real-space. The proposed approach uses an additive separable approximation to the Kohn–Sham Hamiltonian and an L1 localization technique to generate the 1-D localized functions that constitute the Tucker tensor basis. Numerical results show that the resulting Tucker tensor basis exhibits exponential convergence in the ground-state energy with increasing Tucker rank. Further, the proposed tensor-structured algorithm demonstrated sub-quadratic scaling with system-size for both systems with and without a gap, and involving many thousands of atoms. This reduced-order scaling has also resulted in the proposed approach outperforming plane-wave DFT implementation for systems beyond 2000 electrons.


2021 ◽  
Vol 60 (8) ◽  
pp. 6016-6026
Author(s):  
Aydar Rakhmatullin ◽  
Maxim S. Molokeev ◽  
Graham King ◽  
Ilya B. Polovov ◽  
Konstantin V. Maksimtsev ◽  
...  

Author(s):  
Lijuan Meng ◽  
Jinlian Lu ◽  
Yujie Bai ◽  
Lili Liu ◽  
Tang Jingyi ◽  
...  

Understanding the fundamentals of chemical vapor deposition bilayer graphene growth is crucial for its synthesis. By employing density functional theory calculations and classical molecular dynamics simulations, we have investigated the...


2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Long Lin ◽  
Linwei Yao ◽  
Shaofei Li ◽  
Zhengguang Shi ◽  
Kun Xie ◽  
...  

AbstractFinding the active sites of suitable metal oxides is a key prerequisite for detecting CH$$_4$$ 4 . The purpose of the paper is to investigate the adsorption of CH$$_4$$ 4 on intrinsic and oxygen-vacancies CuO (111) and (110) surfaces using density functional theory calculations. The results show that CH$$_4$$ 4 has a strong adsorption energy of −0.370 to 0.391 eV at all site on the CuO (110) surface. The adsorption capacity of CH$$_4$$ 4 on CuO (111) surface is weak, ranging from −0.156 to −0.325 eV. In the surface containing oxygen vacancies, the adsorption capacity of CuO surface to CH$$_4$$ 4 is significantly stronger than that of intrinsic CuO surface. The results indicate that CuO (110) has strong adsorption and charge transfer capacity for CH$$_4$$ 4 , which may provide experimental guidance.


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