New Developments in Raman Spectroscopy with Lasers: Electronic Transitions

1968 ◽  
Vol 22 (5) ◽  
pp. 438-444 ◽  
Author(s):  
J. A. Koningstein
Keyword(s):  
Raman Spectroscopy ◽  
Single Crystals ◽  
Crystal Field ◽  
Raman Spectra ◽  
Raman Effect ◽  
Electronic Transitions ◽  
New Developments ◽  
Selection Rules ◽  
Phonon Spectra ◽  
Host Lattices

A discussion is given of the Raman spectra of single crystals of yttrium gallium garnet (YGaG), of ytterbrium gallium garnet (YbGaG), and of Yb:YGaG. From a comparison of the spectra it has been possible to separate the phonon spectra of the host lattices from that of an electronic Raman effect which occurs between the crystal field levels of the 2F7/2 manifold of Yb3+ in the garnet crystals. Information with respect to the selection rules governing both types of spectra is given.

scholarly journals Synthesis and Structural Properties of Nanocomposites Based on Synthetic Opals and Active Dielectrics

2019 ◽  
Vol 12 (1) ◽  
pp. 19
Author(s):  
Bilal Abu Sal
Keyword(s):  
Raman Spectroscopy ◽  
Single Crystals ◽  
Structural Properties ◽  
Raman Spectra ◽  
Phase Structure ◽  
Opal Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal State ◽  
Synthetic Opals

This work is devoted to generalize and analyze the previouse results of new photonic-crystalline nanomaterials based on synthetic opals and active dielectrics. Data were characterized by X-ray diffraction and Raman spectroscopy. Active dielectrics infiltrated into the pores of the opal from the melt. The phase structure composition of the infiltrated materials into the pores of the opal matrix were analyzed. The results of x-ray diffraction and Raman spectra allowed to establish the crystal state of active dielectrics in the pores of the opal. The Raman spectra of some opal-active dielectric nanocomposites revealed new bands and changes in band intensities compared to the spectra of single crystals of active dielectrics. Further more, differences in band intensities in the spectra were measured at different spots of the sample‘s surface were observed. The revealed changes were attributed to the formation of new crystalline phases due to the injected dielectrics in opal pores.

Second-Order Raman Spectra of Fluorites. I. Critical Point Analysis

1972 ◽  
Vol 50 (8) ◽  
pp. 849-857 ◽  
Author(s):  
N. Krishnamurthy ◽  
V. Soots
Keyword(s):  
Critical Point ◽  
Single Crystals ◽  
Raman Spectra ◽  
Brillouin Zone ◽  
Critical Points ◽  
Photon Counting ◽  
Second Order ◽  
Selection Rules ◽  
Point Analysis ◽  
Critical Point Analysis

With the use of a high-powered Ar+ laser and conventional photon counting techniques it has been possible to observe the second-order Raman spectra of single crystals of CaF2, SrF2, BaF2, and PbF2. The symmetries of the various parts of the spectra of the latter two were determined by using oriented single crystals of these two fluorides. The main features of the observed spectra have been analyzed, with the aid of group-theoretical selection rules, in terms of calculated phonon frequencies at the critical points of the Brillouin zone of these crystals.

G-band Raman Spectra of Isolated Single Wal Carbon Nanotubes: Diameter and Chiraity Dependence

2001 ◽  
Vol 706 ◽  
Author(s):  
A. Jorio ◽  
A. G. Souza Filho ◽  
G. Dresselhaus ◽  
M. S. Dresselhaus ◽  
A. K. Swan ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Antenna Effect ◽  
Selection Rules ◽  
Resonant Raman ◽  
Polarization Studies

AbstractWe present results from resonant Raman spectroscopy on the graphite-like G band by measuring Raman spectra on isolated single wal carbon nanotubes (SWNTs). We discuss the G-band lineshape dependence on nanotube diameter and chirality, as well as polarization studies related to the antenna effect. Symmetry selection rules, dipolar and multipolar antenna behaviors are discussed. Spectra at the single nanotube level are related to spectra observed from SWNT bundles.

Raman spectroscopy of the N–N bond in rare earth dinitrogen complexes

2016 ◽  
Vol 45 (37) ◽  
pp. 14634-14644 ◽  
Author(s):  
Megan E. Fieser ◽  
David H. Woen ◽  
Jordan F. Corbey ◽  
Thomas J. Mueller ◽  
Joseph W. Ziller ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Rare Earth ◽  
Single Crystals ◽  
Raman Spectra ◽  
Relative Stability ◽  
Rare Earth Complexes ◽  
Dinitrogen Complexes

Raman spectra have been collected on single crystals of over 20 different rare earth complexes containing reduced dinitrogen ligands to determine if these data will correlate with periodic properties or relative stability.

Recent Studies of Raman Spectroscopy of Polydiacetylene Crystals: Poly-Ipudo

1992 ◽  
Vol 247 ◽  
Author(s):  
S. H. W. Hankin ◽  
D. J. Sandman
Keyword(s):  
Differential Scanning Calorimetry ◽  
Raman Spectroscopy ◽  
Single Crystals ◽  
Raman Spectra ◽  
Hysteresis Effect ◽  
Temperature Cycling ◽  
Scanning Calorimetry

ABSTRACTUsing 632.8, 514.5, 488.0, and 457.9 nm as wavelengths of excitation, Raman spectra have been observed for single crystals of the polydiacetylene of - (CH2)4OCONHCH(CH3) 2 (Poly-IPUDO). The hysteresis effect observed for the thermochromic shift in the Raman spectra is supported by data from repetitive temperature cycling in differential scanning calorimetry.

scholarly journals Raman Scattering in Non-Stoichiometric Lithium Niobate Crystals with a Low Photorefractive Effect

Crystals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 535 ◽  
Author(s):  
Nikolay Sidorov ◽  
Mikhail Palatnikov ◽  
Alexandra Kadetova
Keyword(s):  
Lithium Niobate ◽  
Single Crystals ◽  
Raman Spectra ◽  
Photorefractive Effect ◽  
Polar Axis ◽  
Symmetry Type ◽  
Selection Rules ◽  
Zn Concentration ◽  
Lithium Niobate Crystals ◽  
Do So

Raman spectra of lithium niobate single crystals strongly doped by zinc and magnesium, it has been established, contain low-intense bands with frequencies 209, 230, 298, 694, and 880 cm−1. Ab ignition calculations fail to attribute these bands to fundamental vibrations of A2 symmetry type unambiguously. Such vibrations are prohibited by the selection rules in the space group C3V6 (R3c). Ab initio calculations also proved that low-intense “extra” bands with frequencies 104 and 119 cm−1 definitely do not correspond to vibrations of A2 symmetry type. We have paid special attention to these extra bands that appear in LiNbO3 single crystals Raman spectra despite the fact that they are prohibited by the selection rules. In order to do so, we have studied a number of lithium niobate single crystals, both nominally pure and doped, by Raman spectroscopy. We have assumed that some “extra” bands correspond to two-particle states of acoustic phonons with a total wave vector equal to zero. We have also detected a Zn concentration area (0.05–0.94 mol.% ZnO in a crystal) where doped crystal structure is more ordered: The order of alternation of the main, doping cations, and vacancies along the polar axis is increased, and oxygen octahedra are less distorted.

Infrared and Raman Spectroscopy of Phonons in n-Type High Tc Superconductors

1989 ◽  
Vol 169 ◽  
Author(s):  
M. K. Crawford ◽  
G. Burns ◽  
G. V. Chandrashekhar ◽  
F. H. Dacol ◽  
W. E. Farneth ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Group Theory ◽  
Single Crystals ◽  
Raman Spectra ◽  
High Tc Superconductors ◽  
High Tc ◽  
Infrared And Raman Spectroscopy ◽  
Ir Reflectance ◽  
Atom Motion

AbstractWe have measured the infrared (IR) reflectance and Raman spectra of electron doped and undoped Nd2CuO4 and Pr2CuO4. Utilizing the results from doped ceramics and undoped ab plane oriented single crystals, we observe and assign all the IR active phonons (3A2u + 4Eu) predicted by group theory. We have also observed the Raman active modes involving atom motion along the c axis. We compare our results to those found in the related hole superconductors based upon La2CuO4.

Raman Spectra of Hexagonal Ethylsulfates of Yttrium and of some Rare Earths

1973 ◽  
Vol 51 (7) ◽  
pp. 1023-1031 ◽  
Author(s):  
G. Schaack ◽  
J. A. Koningstein
Keyword(s):  
Theoretical Calculation ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Raman Spectra ◽  
Rare Earths ◽  
Low Temperatures ◽  
Laser Excitation ◽  
Electronic Transitions ◽  
Line Widths

The phonon Raman spectra of single crystals of Y(C2H5SO4)3•9H2O, Ce(C2H5SO4)3•9H2O, Nd(C2H5SO4)3•9H2O, Sm(C2H5SO4)3•9H2O have been studied at low temperatures with laser excitation. Some information has also been obtained of the compounds of Ho3+ and Er3+. The types of symmetry of the observed modes have been determined and compared with the results of a group theoretical calculation. The internal modes of the C2H5 and SO4 groups and of the H2O molecules can be completely attributed to observed transitions. There is some evidence to attribute the librational modes of the H2O molecules to transitions which show a very pronounced temperature dependence of the line-widths. Reasons for this temperature dependence are discussed. No lines have been found that can be attributed uniquely to electronic transitions.

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