Substituent Effects on the Low‐Frequency Vibrational Modes of Benzoic Acid and Related Compounds

Min, Gao; Zhao, Hongwei; Wang, Wenfeng; Yu, Xin; Li, Wenxin

doi:10.1002/cjoc.200790054

Cited by 12 publications

(1 citation statement)

References 20 publications

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“…In recent years, terahertz (THz) electromagnetic waves have attracted wide attention in molecular recognition due to their unique characteristics of low energy, non-ionization and fingerprint spectrum [1,2]. Since lactose molecules, nucleic acids and DNA have corresponding vibrational fingerprint spectra in the THz range [3], then the THz waves have natural advantages in the field of biomolecular detection [4].…”

Section: Introductionmentioning

confidence: 99%

Terahertz Vibrational Fingerprints Detection of Molecules with Particularly Designed Graphene Biosensors

et al. 2022

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In this research, an arc I-shaped graphene sensing structure with multi-resonance characteristics is proposed for the simultaneous detection of vibrational fingerprints with spectral separation in the terahertz range. The resonant frequencies of the sensor can be dynamically tuned by changing the gate voltage applied to the graphene arrays. The two vibrational fingerprints of lactose molecules (0.53 THz and 1.37 THz) in the transmission spectrum can be enhanced simultaneously by strictly optimizing the geometrical parameters of the sensor. More importantly, these two resonant frequencies can be tuned precisely to coincide with the two standard resonances of the lactose molecule. The physical mechanism of the sensor is revealed by inspection of the electric field intensity distribution, and the advantage of the sensor, which is its ability to operate at a wide range of incident angles, has been demonstrated. The sensing performance of the structure as a refractive index sensor has also been studied. Finally, a double arc I-shaped graphene sensor is further designed to overcome the polarization sensitivity, which demonstrates excellent molecular detection performance under different polarization conditions. This study may serve as a reference for designing graphene biosensors for molecular detection.

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Section: Introductionmentioning

confidence: 99%

Terahertz Vibrational Fingerprints Detection of Molecules with Particularly Designed Graphene Biosensors

et al. 2022

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n‐Butane Monomolecular Cracking on Acidic Zeolites: A Density Functional Study

2008

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Density functional theory was used to study monomolecular cracking reaction of n-butane on acidic zeolite. Geometry optimizations of the local structures of the species reacting with the zeolite were carried out by using the 5T cluster model at the B3LYP/6-311＋G(3df,2p)//B3LYP/6-31G(d) level. In this work, the deprotonation modes of two different order C atoms in n-butane cracking on H-ZSM-5 were explored in detail by the density functional theory. The calculated activation barriers at the B3LYP/6-311＋G(3df,2p)//B3LYP/6-31G(d) level are 238 kJ/mol for the primary C-C cracking, 217 kJ/mol for the secondary C-C cracking, 296 kJ/mol for the primary dehydrogenation, and 242 kJ/mol for the secondary dehydrogenation, respectively. The difference of the activation barrier is 54 kJ/mol for the deprotonation reactions of two different order C atoms in n-butane. For the dehydrogenation reaction, the results indicate that the reaction is expected to be preferred at the secondary C atom. Additionally, the relation between the acidity and structure of the cluster shows that the acidity effect of the zeolite can be simulated by modifying the peripheral bonds of the cluster for the 5T cluster. Finally, the zeolite acidity effects on the reaction barriers were investigated by changing the cluster terminal Si-H bond length.

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Identification of Explosives 2,4‐DNT and 2,6‐DNT Using Terahertz Time‐domain Spectroscopy

Ma¹,

Ma²,

Zhao³

et al. 2008

Chin. J. Chem.

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The absorption spectra and refractive index of 2,4-dinitrotoluene (2,4-DNT) and 2,6-dinitrotoluene (2,6-DNT) were measured in the region of 0.3-2.0 THz by terahertz time-domain spectroscopy (THz-TDS) at room temperature. Gaussian 03 program was applied to predict geometric structure and vibrational frequencies of 2,6-DNT. Three absorption peaks at 1.09, 1.36 and 1.55 THz of 2,6-DNT were obtained and assigned to intermolecular interactions. Quantitative analysis with THz-TDS was undertaken for the mixture of 2,4-DNT and 2,6-DNT. The analytic weight ratio of 2,4-DNT to 2,6-DNT is consistent with the actual one with an analytic error of about 8%.

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Substituent Effects on the Low‐Frequency Vibrational Modes of Benzoic Acid and Related Compounds

Cited by 12 publications

References 20 publications

Terahertz Vibrational Fingerprints Detection of Molecules with Particularly Designed Graphene Biosensors

Terahertz Vibrational Fingerprints Detection of Molecules with Particularly Designed Graphene Biosensors

n‐Butane Monomolecular Cracking on Acidic Zeolites: A Density Functional Study

Identification of Explosives 2,4‐DNT and 2,6‐DNT Using Terahertz Time‐domain Spectroscopy

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