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Low-frequency vibrational modes of glutamine

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Chinese Physics B 2011年第12期20卷 200-204页

作者：王卫宁王果张岩 Beijing Key Laboratory for Terahertz Spectroscopy and Imaging Key Laboratory of Terahertz OptoelectronicsMinistry of EducationDepartment of PhysicsCapital Normal University Department of Chemistry Capital Normal University

High-resolution terahertz absorption and Raman spectra of glutamine in the frequency region 0.2 THz-2.8 THz are obtained by using THz time domain spectroscopy and low-frequency Raman spectroscopy. Based on the experimental and the computational results, the vibration modes corresponding to the terahertz absorption and Raman scatting peaks are assigned and further verified by the theoretical calculations. Spectral investigation of the periodic structure of glutamine based on the sophisticated hybrid density functional B3LYP indicates that the vibrational modes come mainly from the inter-molecular hydrogen bond in this frequency region.

关键词： vibrational modes THz time-domain spectroscopy Raman scattering B3LYP aminoacid

Lattice vibrational modes and phonon thermal conductivity of singlelayer GaGeTe

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Journal of Materiomics 2020年第4期6卷 723-728页

作者： Jingyu Li Peng-Fei Liu Chi Zhang Xiaobo Shi Shujuan Jiang Weizhen Chen Huabing Yin Bao-Tian Wang Institute for Computational Materials Science School of Physics and ElectronicsInternational Joint Research Laboratory of New Energy Materials and Devices of Henan ProvinceHenan UniversityKaifeng 475004China College of Electrical Engineering Henan University of TechnologyZhengzhou450001China Institute of High Energy Physics Chinese Academy of SciencesBeijing100049China Spallation Neutron Source Science Center Dongguan523803China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuanShanxi030006China

Exploring the vibrational properties of experimental or theoretical finding of new phase twodimensional(2D)materials is one key to expand their promising *** GaGeTe monolayer with high carrier mobility,tunable band structure,and low cleavage energy attracts rapidly growing interests in ***,their vibrational modes and phonon properties are not *** on first-principles calculations within the framework of density functional perturbation theory,we systematically study the lattice vibrational modes as well as phonon thermal conductivity of single-layer GaGeTe,which could be exfoliated from the experimentally synthesized GaGeTe *** find that the frequencies and intensities of A1g and Eg Raman modes,contributing to the main peaks in Raman spectra of monolayer GaGeTe,show distinct responses to different external *** calculated lattice thermal conductivity of GaGeTe is about 58 Wm-1 K1,which is comparable to that of MoS2(around 52 Wm1K1)and two orders of magnitude lower than that of graphene(2000 Wm1K1)at room *** is mainly due to the partial couple for acoustic branches and low frequency optic phonon branches,moderate group velocity,strong anharmonic ZA phonon ***,atom substitution at tellurium could be as an effective strategy to further decrease lattice thermal *** findings fill in the gap about the thermal transport properties of GaGeTe monolayer and trigger for further experimental verification of the predicted properties.

关键词： First-principles calculations Phonon thermal conductivity vibrational modes Raman modes

Analysis of vibrational spectra of nano-bio molecules: Application to metalloporphrins

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Chinese Physics B 2013年第9期22卷 225-232页

作者： K Srinivasa Rao G Srinivas J.Vijayasekhar V.U.M.Rao Y.Srinivas K.Sunil Babu V.Sunndadara Siva Kumar A.Hanumaiah Department of Electronics & Instrumentation Engineering Lakireddy Bali Reddy College of Engineering Department of Physics KL University Research Scholar Department of MathematicsJawaharlal Nehru Technological University Department of Applied Mathematics College of Science & TechnologyAndhra University Department of Computer Science GITAM University Department of Physics Miracle Engineering College Department of Electronics & Instrumentation Rajeev Gandhi Memorial Engineering College Department of Physics Lara's Vignan Institute of Technology and Science

In this paper, we have applied the Lie algebraic model to nano-bio molecules to determine the vibrational spectra of different stretching and bending vibrational modes. The determined vibrational energy levels by the Lie algebraic model are compared with the experimental data. The results from the theoretical mode[ are consistent with the experimental data. The vibrational energy levels are clustering in the excited states.

关键词： Lie algebraic model vibrational spectra vibrational modes metalloporphyrins

Raman Spectroscopy of Layered Compound YbB_(2)C_(2)

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Acta Metallurgica Sinica(English Letters) 2021年第7期34卷 1021-1027页

作者： Zhihui Li Jinxing Yang Jiemin Wang Jixin Chen Hao Zhang Cong Cui Xiaohui Wang Zhonghai Ji Yongheng Zhang Meishuan Li Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China

REB_(2)C_(2)(RE=Y and lanthanides)compounds have gained attention for their unique layered crystal ***,there have been few reports about Raman spectroscopy of REB_(2)C_(2) compounds up to ***,the Raman spectrum of YbB_(2)C_(2) is obtained by a micro-Raman spectroscope and the first-principles *** active vibrational modes of YbB_(2)C_(2) are confirmed as A_(1g)(627 and 1311 cm^(-1)),B_(1g)(944 and 1172 cm^(-1)),B_(2g)(330 and 885 cm^(-1))and E_(g)(357 and 530 cm^(-1)).Atomic displacements of these modes are different,they can be divided into two groups:A_(1g)’,B_(1g) and B_(2g) correspond to ring breathing(δ_(in),in the plane)of B_(2)C_(2) layer;E_(g) is due to ring deformation(δ_(oop),out of the plane)of B_(2)C_(2) *** results are helpful to understand the individual structure of REB_(2)C_(2).

关键词： YbB_(2)C_(2) Layered compound Raman spectroscopy First-principles calculations vibrational modes

Low-frequency hybridized excess vibrations of two-dimensional glasses

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Chinese Physics B 2024年第5期33卷 550-555页

作者：付立存郑一鸣王利近 School of Physics and Optoelectronic Engineering Anhui UniversityHefei 230601China

One hallmark of glasses is the existence of excess vibrational modes at low frequenciesωbeyond Debye’s *** studies suggest that understanding low-frequency excess vibrations could help gain insight into the anomalous mechanical and thermodynamic properties of ***,there is still intensive debate as to the frequency dependence of the population of low-frequency excess *** particular,excess modes could hybridize with phonon-like modes and the density of hybridized excess modes has been reported to follow D_(exc)(ω)~ω^(2)in 2D glasses with an inverse power law ***,the universality of the quadratic scaling remains unknown,since recent work suggested that interaction potentials could influence the scaling of the vibrational ***,we extend the universality of the quadratic scaling for hybridized excess modes in 2D to glasses with potentials ranging from the purely repulsive soft-core interaction to the hard-core one with both repulsion and attraction as well as to glasses with significant differences in density or interparticle ***,we observe that the number of hybridized excess modes exhibits a decrease in glasses with higher density or steeper interparticle repulsion,which is accompanied by a suppression of the strength of the sound *** results indicate that the density bears some resemblance to the repulsive steepness of the interaction in influencing low-frequency properties.

关键词： density of states vibrational modes sound attenuation two-dimensional glasses

Effect of Cu/Zn Substitution in MgO Nanostructures for Tuning the Optical Bandgap and Structural Properties

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Journal of Wuhan University of Technology(Materials Science) 2022年第6期37卷 1035-1040页

作者： ATIF Dawar S NASEEM Shah M ASIF Siddiqui YASMEEN Bibi Department of Physics Federal Urdu University of ArtsScience and TechnologyKarachiPakistan Department of Chemistry Federal Urdu University of ArtsScience and TechnologyKarachiPakistan

Low cost co-precipitation method was used to synthesize Cu(0-0.05)doped MgO samples with fixed concertation of Zn=0.01.X-ray diffraction(XRD)spectra confirmed the phase purity of the samples for 0≤Cu≤0.03 doping *** secondary phase for 0.04≤Cu≤0.05 exhibited the formation of mixed metal *** crystallite size was found to increase from 17.5 to 23.5 nm for 0≤Cu≤0.03 and then decreased from 22 to 18.5 nm for 0.04≤Cu≤*** estimated bandgap first reduced from 5.48 to 4.88 eV and then increased from 5.21 to 5.36 *** morphology of the samples transformed from spheroidal shape to star-like *** obtained results reveal that the structural and optical property are in good agreement with the morphological *** peak shifting towards the lower values of vibrational frequency from 694 to 579 cm^(-1) confirms the incorporation of Cu/Zn in Mg-O *** tuning of optical bandgap and structural properties with varying dopant concentration in MgO nanomaterials can be used for multifunctional modern energy storage and optoelectronic devices.

关键词： Cu/Zn doping MgO optical bandgap morphology vibrational modes