scholarly journals Investigation of thermostability of Mo6S3I6 nanowires using Raman spectroscopy

2009 ◽  
Vol 63 (3) ◽  
pp. 217-220
Author(s):  
Jelena Todorovic ◽  
Dejan Djokic ◽  
Zorana Dohcevic-Mitrovic ◽  
Dragan Mihailovic ◽  
Zoran Popovic
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Room Temperature ◽  
Group Analysis ◽  
Temperature Treatment ◽  
Incident Laser ◽  
Chevrel Phase ◽  
Incident Laser Power ◽  
Raman Modes ◽  
Good Agreement

The thermostability (phase stability) of Mo6S3I6 nanowires was investigated by Raman spectroscopy, varying the incident laser power (1-9 mW) or by gradual heating of the sample from room temperature to 600?C. We have noticed 18 Raman modes in the room temperature Raman spectra, which is in good agreement with the factor group analysis prediction for P1 space group. We confirmed that the vibrations of Mo6S8 clusters dominate in vibrational properties of the Mo6S3I6 nanostructure, since nanowires Raman spectra are similar to Chevrel phase Raman spectra. During the temperature treatment, it was established that in the temperature range between 300 and 400?C a new Raman mode appeares. This mode can be ascribed to molybdenum oxide (MoO3). With further temperature increase, the intensity of this mode increases, drawing a conclusion that at temperature above 300?C the phase separation takes place in this system followed by a formation of oxide layer.

Liquid Core Optical Fibers in Raman Spectroscopy

1981 ◽  
Vol 35 (4) ◽  
pp. 439-442 ◽  
Author(s):  
Howard B. Ross ◽  
William M. McClain
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Optical Fibers ◽  
Liquid Core ◽  
Geometrical Optics ◽  
Laser Spectrometer ◽  
Trans Stilbene ◽  
Scan Speed ◽  
Good Agreement

Raman spectra of samples contained in hollow quartz fibers are compared quantitatively to conventional Raman spectra using identical laser, spectrometer, detector, and scan speed. We find the fiber signal to be enhanced by a factor of 250/m of fiber, in good agreement with calculations based on geometrical optics. A fiber spectrum of 2 mol% trans-stilbene in benzene is good enough to allow essentially perfect solvent subtraction.

Raman study of the structural properties of KNO3(II)

1977 ◽  
Vol 55 (7) ◽  
pp. 1242-1250 ◽  
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.

PREFERENTIAL ORIENTATION GROWTH OF AlN THIN FILMS ON Si(111) SUBSTRATES BY PLASMA-ASSISTED MOLECULAR BEAM EPITAXY

2009 ◽  
Vol 16 (06) ◽  
pp. 925-928 ◽  
Author(s):  
L. S. CHUAH ◽  
Z. HASSAN ◽  
H. ABU HASSAN
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
X Ray Diffraction ◽  
X Ray ◽  
Micro Raman Spectroscopy ◽  
Raman Modes ◽  
Orientation Growth ◽  
Good Agreement

This article reports the use of plasma-assisted molecular beam epitaxy (MBE) to grow AlN on Si (111) substrate at 850°C under UHV conditions for 15, 30, and 45 min. The films were characterized by high-resolution X-ray diffraction (HR-XRD) and micro-Raman spectroscopy. XRD measurement revealed that the AlN was epitaxially grown on Si (111). Micro-Raman result showed that all the allowed Raman modes of AlN and Si were clearly visible. Fourier transform infrared (FTIR) spectroscopy has been used to investigate the A1 (LO) and E1 (TO) modes with frequencies (890–899) cm-1 and (668–688) cm-1, respectively. The results are in good agreement with reported phonon frequencies of AlN grown on Si (111).

Self-Focusing of Laser Light and Stimulated Scattering Processes in Transparent and Absorbing Liquids: 1. Self-Focusing

1970 ◽  
Vol 25 (12) ◽  
pp. 1868-1879 ◽  
Author(s):  
M. Maier ◽  
O. Rahn ◽  
G. Wendl
Keyword(s):  
Laser Power ◽  
Laser Light ◽  
Beam Diameter ◽  
Incident Laser ◽  
Stimulated Scattering ◽  
Light Pulses ◽  
Incident Laser Power ◽  
Self Focusing ◽  
Stimulated Brillouin ◽  
Good Agreement

Abstract The spatial and temporal development of self-focusing of light pulses is investigated. The beam diameter in CS2 and molten para-di-chlorobenzene decreases with increasing incident laser power to small values in good agreement with theory. The strong influence of beam divergence, non-linearity of refractive index, and absorption on self-focusing action is found to agree well with numerical calculations. It is shown that both backward stimulated Brillouin and Raman scattering terminate the self-focusing process.

A structural investigation of the singly layered silicates, silinaite and makatite, by vibrational spectroscopy

1999 ◽  
Vol 77 (4) ◽  
pp. 495-501 ◽  
Author(s):  
Yining Huang ◽  
Zhimei Jiang ◽  
Wilhelm Schwieger
Keyword(s):  
Raman Spectra ◽  
Vibrational Spectroscopy ◽  
Structural Investigation ◽  
Group Analysis ◽  
Factor Group ◽  
Layered Silicates ◽  
Ir And Raman Spectra ◽  
Vibrational Modes ◽  
Ir And Raman ◽  
Good Agreement

The IR and Raman spectra of two singly layered silicates, silinaite and makatite, have been investigated. The vibrational spectra were assigned based on previous studies of various silicates. The correlation between vibrational modes and the structural properties of silicates under investigation has been made. The IR and Raman spectra of silinaite are in good agreement with the known structure. However, the observed vibrational data of makatite are not completely consistent with those predicted by a factor group analysis based on the published single-crystal data.Key words: layered silicates, silinaite, makatite, vibrational spectroscopy.

Raman spectra of charge transfer organic compounds: Conductors And Semiconductors

1995 ◽  
Vol 413 ◽  
Author(s):  
R. Gómez ◽  
R. Ridaura ◽  
M. Quintana ◽  
M. L. Marquina ◽  
V. Marquina ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Charge Transfer ◽  
Raman Spectra ◽  
Coordination Compounds ◽  
Room Temperature ◽  
Molecular Solids ◽  
Donor And Acceptor ◽  
Ft Ir ◽  
Degree Of Charge Transfer

ABSTRACTA series of coordination compounds -macrocycle tetraaza derivatives with extended electronic conjugations- as molecular solids have been synthesized and analyzed by Raman spectroscopy. Their resistivity vs. temperature characteristics, measured in thin films, show three types of behavior: metallic, semiconductor and, in some cases, semiconductor with a transition to metallic below certain temperature. Room temperature Raman spectra were obtained in a FT-IR spectrometer and some stretching modes show different Raman shifts depending on the reactants. We relate these shifts with the degree of charge transfer between donor and acceptor radicals.

scholarly journals Raman Spectra of High-κDielectric Layers Investigated with Micro-Raman Spectroscopy Comparison with Silicon Dioxide

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
P. Borowicz ◽  
A. Taube ◽  
W. Rzodkiewicz ◽  
M. Latek ◽  
S. Gierałtowska
Keyword(s):  
Raman Spectroscopy ◽  
Silicon Dioxide ◽  
Raman Spectra ◽  
Hafnium Oxide ◽  
Silicon Oxide ◽  
Temperature Treatment ◽  
Silicon Dioxide Layer ◽  
Micro Raman Spectroscopy ◽  
Lutetium Oxide ◽  
Three Samples

Three samples with dielectric layers from high-κdielectrics, hafnium oxide, gadolinium-silicon oxide, and lanthanum-lutetium oxide on silicon substrate were studied by Raman spectroscopy. The results obtained for high-κdielectrics were compared with spectra recorded for silicon dioxide. Raman spectra suggest the similarity of gadolinium-silicon oxide and lanthanum-lutetium oxide to the bulk nondensified silicon dioxide. The temperature treatment of hafnium oxide shows the evolution of the structure of this material. Raman spectra recorded foras-depositedhafnium oxide are similar to the results obtained for silicon dioxide layer. After thermal treatment especially at higher temperatures (600°C and above), the structure of hafnium oxide becomes similar to the bulk non-densified silicon dioxide.

STUDY ON PHOTOBLEACHING OF METHYLENE BLUE DOPED IN PMMA, PVA AND GELATIN USING PHOTOACOUSTIC TECHNIQUE

2003 ◽  
Vol 12 (01) ◽  
pp. 91-100 ◽  
Author(s):  
W. MAHMOOD MAT YUNUS ◽  
KOK SHENG CHAN ◽  
WAN MD. ZIN WAN YUNUS
Keyword(s):  
Methylene Blue ◽  
Raman Spectroscopy ◽  
Thermal Diffusivity ◽  
Laser Power ◽  
Solid Matrix ◽  
Beam Power ◽  
Poly Vinyl Alcohol ◽  
Photoacoustic Technique ◽  
Incident Laser ◽  
Incident Laser Power

The photobleaching of Methylene blue embedded in the solid matrix PMMA (poly(methylmethacrylate)), PVA (poly(vinyl alcohol)) and gelatin has been investigated using a photoacoustic technique. Photoacoustic signals were measured as a function of time, chopping frequency, and the beam power. Experimental results indicate that the photobleaching rate is proportional to the incident laser power (260–300 mW) and decreased with increasing the concentration of dopant molecules. Methylene blue embedded in PVA shows the highest photobleaching rate then followed by gelatin and PMMA. The increase of photobleaching rate in PVA is also noticed when the beam power is increased. The thermal diffusivity values obtained for bleached PMMA, PVA and gelatin are 1.46 × 10-3 cm2/s , 0.83 × 10-3, cm2/s and 1.10 × 10-3 cm2/s respectively. Spectrophotometer and Raman spectroscopy were used to confirm the photoacoustic results.

scholarly journals Identifying Raman modes of Sb2Se3 and their symmetries using angle-resolved polarised Raman spectra

2020 ◽  
Vol 8 (17) ◽  
pp. 8337-8344 ◽  
Author(s):  
Nicole Fleck ◽  
Theodore D. C. Hobson ◽  
Christopher N. Savory ◽  
John Buckeridge ◽  
Tim D. Veal ◽  
...  
Keyword(s):  
Thin Films ◽  
Density Functional Theory ◽  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Density Functional ◽  
Functional Theory ◽  
Raman Modes

Vibrational symmetry assignments using Raman spectroscopy and density functional theory on oriented crystals also enabling orientation optimisation of thin films.

Studies on Raman Spectra of Cu2+ Ion Doped B2O3-K2O-ZnO-BaO Glasses

2017 ◽  
Vol 13 (1) ◽  
pp. 4495-4498
Author(s):  
L.S. Ravangave ◽  
G.N. Devde
Keyword(s):  
Raman Spectroscopy ◽  
Structural Properties ◽  
Raman Spectra ◽  
Experimental Technique ◽  
Room Temperature ◽  
Copper Ion ◽  
Membered Ring ◽  
Melt Quenching ◽  
Present Glass ◽  
Local Arrangement

Glasses with compositions 59B2O3-10K2O-(30-x)ZnO-xBaO-1CuO were prepared using melt quenching technique. The effect of BaO content in present glass system doped with copper ion in place of ZnO has been studied with respect to structural properties. Raman spectroscopy is an experimental technique appropriate for providing information about  the structure, local arrangement of the atoms in the present glasses. The Raman spectra of glasses were recorded at room temperature in the range 200-1800 cm-1 using a He-Ne excitation source having wavelength 632.81 nm. The Raman peaks appeared around 760 cm-1 assigned symmetric breathing vibrations of six-membered ring with both BO3 triangle and BO4 tetrahedral. The intensity of these peaks is slightly varied with the addition of BaO content while the broadness is found to be larger at 30 mol% of BaO than 30 mol% ZnO. This indicates that certain BO4 units could be preferentially converted while those in ring groups could be stabilized. Raman studies it is concluded that present glasses are composed of [BO4] and [BO3] units in metaborate, orthoborate, diborate groups.

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