Low frequency Raman spectra of the liquid and plastic crystal phases of O2, N2, CO, and of Ar crystals with these molecules as guests

Low frequency Raman spectra of single crystals of orientationally disordered phases of oxygen, nitrogen, and carbon monoxide, and spectra of those substances as liquids show two linear segments in semi-log plots. Slopes of the higher frequency segments are nearly equal for all cases; slopes of the lower frequency segments are particular to the substance and are nearly the same in both liquid and crystal for O2 and CO. Spectra of single crystals of argon doped with O2, N2, or CO show two distinct features superimposed on a sloping background. Impurity molecule reorientation apparently accounts satisfactorily for all spectral features, but translation–rotation coupling may allow a contribution to the higher frequency feature arising from a local phonon mode in argon.

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Raman study of the structural properties of KNO3(II)

Canadian Journal of Chemistry ◽

10.1139/v77-172 ◽

1977 ◽

Vol 55 (7) ◽

pp. 1242-1250 ◽

Cited By ~ 32

Author(s):

M. H. Brooker

Keyword(s):

Single Crystals ◽

Structural Properties ◽

Raman Spectra ◽

Excellent Agreement ◽

Room Temperature ◽

Group Analysis ◽

Factor Group ◽

Spectral Features ◽

Space Group ◽

Raman Study

Raman spectra of oriented single crystals of KNO3(II) have been recorded at 298 and 77 K. At both temperatures the data are in excellent agreement with the factor group analysis based on the generally accepted Pmcn space group. Additional spectral features observed near room temperature suggest the presence of a significant number of disordered nitrate groups on alternate lattice sites, although the majority of nitrate groups occupy the ordered sites. As the temperature is lowered, the disordered groups freeze out until near the temperature of reported electrical anomalies (213 K) only the ordered sites are occupied. Improved resolution has resulted in detection of a number of new spectral features while improved depolarization data have resulted in reassignment of several peaks.

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Temperature Dynamics for Low-Frequency Raman Spectra of Progesterone, 17α-Hydroxyprogesterone and Cortisone

Siberian Journal of Physics ◽

10.54362/1818-7919-2010-5-4-168-172 ◽

2010 ◽

Vol 5 (4) ◽

pp. 168-172

Author(s):

Оlga P. Cherkasova ◽

Vladimir A. Volodin ◽

Valentina A. Minaeva ◽

Boris F. Minaev ◽

Gleb V. Baryshnikov

Keyword(s):

Raman Spectra ◽

Density Functional Calculations ◽

Density Functional ◽

Low Frequency ◽

Vibrational Frequencies ◽

Frequency Region ◽

Spectral Features ◽

Temperature Dynamics

The Raman spectra of progesterone, 17α-hydroxyprogesterone and cortisone in the low-frequency region are studied. Several intense spectral features demonstrate clear temperature dynamics in the range of 83 K. Assignment of vibrational frequencies is performed with the use of density functional calculations at the B3LYP/6-31G(d,p) level. The observed spectral features are assigned to vibrations of the whole skeleton including substituents at the С 17 atom

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Evaluation of Raman Scattering in La1-xMxMnO3 Single Crystals Due to Structural and Magnetic Transitions

MRS Proceedings ◽

10.1557/proc-494-329 ◽

1997 ◽

Vol 494 ◽

Cited By ~ 1

Author(s):

V. B. Podobedovm ◽

A. Weber ◽

D. B. Romero ◽

J. P. Rice ◽

H. D. Drew

Keyword(s):

Raman Scattering ◽

Single Crystals ◽

Raman Spectra ◽

Phonon Scattering ◽

Strong Dependence ◽

Low Frequency ◽

Anomalous Behavior ◽

Magnetic Phase Transitions ◽

Raman Mode ◽

Jahn Teller

ABSTRACTThe study of doped and undoped La1-xMxMnO3 single crystals (x = 0 to x = 0.3) in the temperature range from 5 K to 423 K is reported. The activity of phonon vibrational modes in optical spectra is analyzed and a comparison to experimental Raman data is presented. Different contributions from optical phonons to the Raman scattering process are discussed. It is shown that both the value of doping and temperature have a significant influence on Raman features, and these are strongly affected by structural and magnetic phase transitions. Due to the symmetry present in distorted lanthanum manganese compounds their Raman spectra were found to contain comparable contributions from first- and second-order phonon scattering. The common features related to both the reduction of the Jahn-Teller (JT) distortion and the temperature-induced phase transition were found in the Raman spectra of La1-xMxMnO3 crystals. An anomalous behavior of the low-frequency Raman mode in doped systems was found and explained in terms of the temperature-dependent ionic radius of the La/Sr ion sites. It was found that the strong dependence of the Ag Raman mode on the value of doping may serve as a useful tool for optical characterization of La1-xMxMnO3 compounds, including the inhomogeneity of the surface.

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Low-Frequency Central Peaks In Relaxor Ferroelectric PZN-9%PT Single Crystals

Ferroelectrics ◽

10.1080/00150190601186916 ◽

2007 ◽

Vol 347 (1) ◽

pp. 25-29 ◽

Cited By ~ 3

Author(s):

Jae-Hyeon Ko ◽

Do Han Kim ◽

Seiji Kojima

Keyword(s):

Single Crystals ◽

Low Frequency ◽

Relaxor Ferroelectric

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Investigations on Crystalline Perfection, Raman Spectra and Optical Characteristics of Transition Metal (Ru) Co-Doped Mg:LiNbO3 Single Crystals

ACS Omega ◽

10.1021/acsomega.1c00452 ◽

2021 ◽

Author(s):

M. K. Raseel Rahman ◽

B. Riscob ◽

Rajeev Bhatt ◽

Indranil Bhaumik ◽

Sarveswaran Ganesamoorthy ◽

...

Keyword(s):

Transition Metal ◽

Single Crystals ◽

Raman Spectra ◽

Optical Characteristics ◽

Crystalline Perfection ◽

Co Doped

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Research on comment target extracting in Chinese online shopping platform

International Journal of Crowd Science ◽

10.1108/ijcs-09-2018-0019 ◽

2018 ◽

Vol 2 (3) ◽

pp. 247-258

Author(s):

Zhishuo Liu ◽

Qianhui Shen ◽

Jingmiao Ma ◽

Ziqi Dong

Keyword(s):

Association Rule ◽

Online Shopping ◽

Low Frequency ◽

Online Reviews ◽

Content Type ◽

Pos Tagging ◽

Part Of Speech ◽

Frequency Feature ◽

Practical Implications ◽

Data Reading

Purpose This paper aims to extract the comment targets in Chinese online shopping platform. Design/methodology/approach The authors first collect the comment texts, word segmentation, part-of-speech (POS) tagging and extracted feature words twice. Then they cluster the evaluation sentence and find the association rules between the evaluation words and the evaluation object. At the same time, they establish the association rule table. Finally, the authors can mine the evaluation object of comment sentence according to the evaluation word and the association rule table. At last, they obtain comment data from Taobao and demonstrate that the method proposed in this paper is effective by experiment. Findings The extracting comment target method the authors proposed in this paper is effective. Research limitations/implications First, the study object of extracting implicit features is review clauses, and not considering the context information, which may affect the accuracy of the feature excavation to a certain degree. Second, when extracting feature words, the low-frequency feature words are not considered, but some low-frequency feature words also contain effective information. Practical implications Because of the mass online reviews data, reading every comment one by one is impossible. Therefore, it is important that research on handling product comments and present useful or interest comments for clients. Originality/value The extracting comment target method the authors proposed in this paper is effective.

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Spatial Correlation Interpretation of Effects of As+ Implantation on the Raman Spectra of GaAs

MRS Proceedings ◽

10.1557/proc-27-305 ◽

1983 ◽

Vol 27 ◽

Author(s):

D.E. Aspnes ◽

K.K. Tiong ◽

P.M. Amirtharaj ◽

F.H. Pollak

Keyword(s):

Spatial Correlation ◽

Raman Spectra ◽

Selection Rule ◽

Phonon Mode ◽

Red Shift ◽

Correlation Model ◽

Model Based ◽

Ion Implanted

ABSTRACTThe red shift and asymmetric broadening of the LO phonon mode of ion-implanted GaAs are both described quantitatively by a spatial correlation model based on a damage-induced relaxation of the momentum selection rule previously used by Richter, Wang, and Ley to describe similar effects in microcrystalline Si. The success of the model for a qualitatively different disorder microstructure suggests it may be possible to evaluate average sizes of crystallographically perfect regions in semiconductors from the phonon lineshapes of their Raman spectra.

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