pinecone/core-2020-05-10-deduplication huggingface dataset:
Raman spectroscopic study of the uranyl oxyhydroxide hydrates : becquerelite, billietite, curite, schoepite and vandendriesscheite

Raman and infrared spectra of five uranyl oxyhydroxide hydrates, becquerelite, billietite, curite, schoepite and vandendriesscheite are reported. Observed bands are attributed to the (UO2)2+ stretching and bending vibrations, U-OH bending vibrations, H2O and (OH)- stretching, bending and libration modes. U-O bond lengths in uranyls and O-H…O bond lengths are calculated from the wavenumbers assigned to the stretching vibrations. They are close to the values inferred and/or predicted from the X-ray single crystal structure. The complex hydrogen-bonding network arrangement was proved in the structures of all minerals studied. This hydrogen bonding contributes to the stability of these uranyl minerals
Raman bands of double-wall carbon nanotubes: comparison with single- and triple-wall carbon nanotubes, and influence of annealing and electron irradiation

We compare the G and G2D bands of single-, double- and triple-wall carbon nanotubes (CNTs). We observe that the band shape is sensitive to the number of walls of the CNTs. For single-wall carbon nanotubes (SWCNTs), the G band is composed of two distinct contributions G+ and G-, while the G band for double-wall nanotubes is composed of one band with two main contributions from the inner and the outer tube. The G2D band can be fitted with one Lorentzian for single-wall tubes, while two distinct contributions are observed for double-wall carbon nanotubes (DWCNTs). Considerable variations of the G2D band are found with similar first order Raman spectra. Annealing influences the D- and RBM-band intensities. Electron irradiation has the effect of decreasing the G- and D-band wavenumbers but does not enhance the D-band intensity considerably. The down-shifts of the G- and D-band wavenumbers are correlated and are the same for two excitation wavelengths. This is consistent with the scattering of phonons around the K-point
Polarizability calculation of vibrating nanoparticles for intensity of
  low frequency Raman scattering

A new numerical method is introduced for calculating the polarizability of an
arbitrary dielectric object with position dependent complex permittivity. Three
separate numerical approaches are provided to calculate the dipole moment of a
nanoparticle embedded in a dielectric matrix in the presence of an applied
electric field. Numerical tests confirm the accuracy of this method when
applied to several cases for which an exact solution is available. This method
is especially well suited for the calculation of absolute Raman scattering
intensities due to acoustic phonons in metallic and dielectric nanoparticles
embedded in transparent matrices.Comment: Submitted to the Journal of Raman Spectroscop
Raman spectroscopy of the sampleite group of minerals

Raman and infrared spectroscopy has enabled insights into the molecular structure of the sampleite group of minerals. These minerals are based upon the incorporation of either phosphate or arsenate with chloride anion into the structure and as a consequence the spectra refect the bands attributable to these anions, namely phosphate or arsenate with chloride. The sampleite vibrational spectrum reflects the spectrum of the phosphate anion and consists of ν1 at 964, ν2 at 451 cm-1, ν3 at 1016 and 1088 and ν4 at 643, 604, 591 and 557 cm-1.  The lavendulan spectrum consists of ν1 at 854, ν2 at 345 cm-1, ν3 at 878 cm-1 and ν4 at 545 cm-1.  The Raman spectrum of lemanskiite is different from that of lavendulan consistent with a different structure. Low wavenumber bands at 227 and 210 cm-1 may be assigned to CuCl TO/LO optic vibrations. Raman spectroscopy identified the substitution of arsenate by phosphate in zdenekite and lavendulan
Raman spectroscopy of the joaquinite minerals

Selected joaquinite minerals have been studied by Raman spectroscopy.  The minerals are categorised into two groups depending upon whether bands occur in the 3250 to 3450 cm-1 region and in the 3450 to 3600 cm-1 region or in the latter region only. The first set of bands is attributed to water stretching vibrations and the second set to OH stretching bands. In the literature X-ray diffraction could not identify the presence of OH units in the structure of joaquinite. Raman spectroscopy proves that the joaquinite mineral group contain OH units in their structure and in some cases both water and OH units.  A series of bands at 1123, 1062, 1031, 971, 912 and 892 cm-1 are assigned to SiO stretching vibrations. Bands above 1000 cm-1 as attributable to νas modes of the (SiO4)4- and (Si2O7)6- units.  Bands are observed at 738, around 700, 682, around 668, 621 and 602 cm-1 are attributed to O-Si-O bending modes. The patterns do not appear to match the published infrared patterns of either (SiO4)4-  or (Si2O7)6- units.  The reason is attributed to the actual formulation of the joaquinite mineral in which significant amounts of Ti or Nb and Fe are found
Raman spectroscopy of dawsonite NaAl(CO3)(OH)2

Raman spectroscopy at both 298 and 77 K complimented with infrared spectroscopy has been used to study the structure of dawsonite. Previous crystallographic studies concluded that the structure of dawsonite was a simple one, however both Raman and infrared spectroscopy show that this conclusion is incorrect. Multiple bands are observed in both the Raman and infrared spectra in the antisymmetric stretching and bending regions showing that the symmetry of the carbonate anion is reduced and in all probablity the carbonate anions are not equivalent in the dawsonite structure. Multiple OH deformation vibrations centred upon 950 cm-1 in both the Raman and infrared spectra show that the OH units in the dawsonite structure are non-equivalent.  Calculations using the position of the Raman and infrared OH stretching vibrations enabled estimates of the hydrogen bond distances of  0.2735, 0.27219 pm at 298 K  and  0.27315, 0.2713 pm at 77 K to be made. This indicates strong hydrogen bonding of the OH units in the dawsonite structure
Natural halotrichites – an EDX and Raman spectroscopic study

Raman spectroscopy has been used to characterise four natural halotrichites: halotrichite FeSO4.Al2(SO4)3. 22H2O, apjohnite MnSO4.Al2(SO4)3.22H2O, pickingerite MgSO4.Al2(SO4)3.22H2O and wupatkiite CoSO4.Al2(SO4)3.22H2O. A comparison of the Raman spectra is made with the spectra of the equivalent synthetic pseudo-alums. Energy dispersive X-ray analysis (EDX) was used to determine the exact composition of the minerals. The Raman spectrum of apjohnite and halotrichite display intense symmetric bands at 985 cm-1 assigned to the v1(SO4)2- symmetric stretching mode. For pickingerite and wupatkiite, an intense band at 995 cm-1 is observed. A second band is observed for these minerals at 976 cm-1 attributed to a water librational mode \ud
The series of bands for apjohnite at 1104, 1078 and 1054 cm-1, for halotrichite at 1106, 1072 and 1049 cm-1, for pickingerite at 1106, 1070 and 1049 cm-1 and for wupatkiite at 1106, 1075 and 1049 cm-1 are attributed to the v3(SO4)2- antisymmetric stretching modes of v3(Bg) SO4. Raman bands at around 474, 460 and 423 cm-1 are attributed to the v2(Ag) SO4 mode. The band at 618 cm-1 is assigned to the 4(Bg) SO4 mode. The splitting of the v2, v3 and v4 modes is attributed to the reduction of symmetry of the SO4 and it is proposed that the sulphate coordinates to water in the hydrated aluminium in bidentate chelation
A Raman spectroscopic study of the uranyl carbonate rutherfordine

The molecular structure of the uranyl mineral rutherfordine has been investigated by the measurement of the Raman spectra at 298 and 77 K and complemented with infrared spectra. The infrared spectra of the (CO3)2- units in the antisymmetric stretching region show complexity with three sets of carbonate bands observed. This combined with the observation of multiple bands in the (CO3)2- bending region in both the Raman and IR spectra suggests that both monodentate and bidentate (CO3)2- units are present in the structure in accordance with the X-ray crystallographic studies. Complexity is also observed in the IR spectra of (UO2)2+ antisymmetric stretching region and is attributed to non-identical UO bonds. Both Raman and infrared spectra of the rutherfordine show the presence of both water and hydroxyl units in the structure as evidenced by IR bands at 3562 and 3465 cm-1 (OH) and 3343, 3185 and 2980 cm-1 (H2O).  Raman spectra show the presence of four sharp bands at 3511, 3460, 3329 and 3151 cm-1
Raman spectroscopy of halogen-containing carbonates

Raman spectroscopy complimented with infrared spectroscopy has been used to study a series of selected natural halogenated carbonates from different origins including bastnasite, parisite and northupite.  The position of CO32-  symmetric stretching vibration varies with mineral composition. An additional band for northupite at 1107 cm-1 is observed. Raman spectra of bastnasite, parisite and northupite show a single band at 1433, 1420 and 1554  cm-1 respectively, assigned to the ν3 (CO3)2- asymmetric stretching mode.  The observation of additional Raman bands for the ν3 modes for some halogentaed carbonates is significant in that it shows distortion of the CaO6 octahedron  No ν2 Raman bending modes are observed for these minerals. The band is observed in the infrared spectra and multiple ν2 modes at 844 and 867 cm-1 are observed for parisite. A single intense infrared band is found at 879 cm-1 for northupite.  Raman bands are observed for the carbonate ν4 in phase bending modes at 722 cm-1 for bastnasite, 736 and 684 cm-1 for parisite, 714 cm-1 for northupite.  Multiple bands are observed in the OH stretching region for selected bastansites and parisites indicating the presence of water and OH units in the mineral structure. The presence of such bands brings into question the actual formula of these halogenated carbonate minerals
Synthesis and Raman spectroscopic characterisation of hydrotalcite with CO32- and VO3- anions in the interlayer

Infrared and Raman spectroscopy have been used to characterise synthetic mixed carbonate and vanadate hydrotalcites of formula Mg6Al2(OH)16(CO3)2-,(VO4)3-.4H2O. The spectra have been used to assess the molecular assembly of the cations and anions in the hydrotalcite structure. The spectra may be conveniently subdivided into spectral features based (a) upon the carbonate anion (b) the hydroxyl units (c) water units. Bands are assigned to the hydroxyl stretching vibrations of water. Three types of carbonate anions are identified (a) carbonate hydrogen bonded to water in the interlayer (b) carbonate hydrogen bonded to the hydrotalcite hydroxyl surface and (c) free carbonate anions. It is proposed that the water is highly structured in the hydrotalcite as it is hydrogen bonded to both the carbonate and the hydroxyl surface. The spectra have been used to assess the contamination of carbonate in an open reacting vessel in the synthesis of a vanadate hydrotalcites of formula Mg6Al2(OH)16(CO3)2-,(VO4)3-.4H2O. Bands have been assigned to vanadate anions in the infrared and Raman spectra associated with V-O bonds
Antioxidant phenolic esters with potential anticancer activity: A Raman spectroscopy study

A Raman study of hydroxycinnamic and hydroxybenzoic esters (caffeates, ferulates and gallates) displaying antioxidant and anticancer properties was undertaken, with particular emphasis on the analysis of the effect of the ring substituents and the nature of the ester alkyl chain on their spectroscopic features. A complete assignment of the spectra was carried out for all the compounds investigated, in the light of the corresponding calculated wavenumbers (at the density functional theory level). Distinct vibrational patterns were observed for each type of ester, thereby allowing their ready characterisation and identification by Raman spectroscopy. Evidence of the occurrence of intermolecular hydrogen bonds, leading to the formation of dimers in the condensed phase, was also obtained. Copyright © 2007 John Wiley & Sons, Ltd.http://dx.doi.org/10.1002/jrs.182
Raman spectroscopic study of the multi-anion uranyl mineral schroeckingerite

Raman spectroscopy complimented with infrared spectroscopy has been used to study the mineral schroeckingerite.  The mineral is a multi-anion mineral and has (UO2)2+, (SO4)2-, and (CO3)2- units in its structure and bands attributed to these vibrating units are readily identified in the Raman spectra. Symmetric stretching modes at 815, 983 and 1092 cm-1 are assigned to (UO2)2+, (SO4)2-, and (CO3)2- units, respectively. The antisymmetric stretching modes of (UO2)2+, (SO4)2- are not observed in the Raman spectra but may be readily observed in the infrared spectrum at 898 and 1180 cm-1.  The antisymmetric stretching mode of (CO3)2- is observed in the Raman spectrum at 1374 cm-1 as is also the ν4 (CO3)2- bending modes at 742 and 707 cm-1. No ν2 (CO3)2- bending modes are observed in the Raman spectrum of schroeckingerite.  All the spectroscopic evidence points to a highly ordered structure of this mineral
Raman spectroscopic study of the uranyl carbonate mineral voglite

Raman spectroscopy complimented with infrared spectroscopy has been used to study the uranyl carbonate mineral voglite.  The mineral has the formula Ca2Cu2+\[(UO2)(CO3)3](CO3).6H2O and bands attributed to these vibrating units are readily identified in the Raman spectrum. Symmetric stretching modes at 836 and 1094 cm-1 are assigned to v1 (UO2)2+, and v1 (CO3)2- units. The v3 antisymmetric stretching modes of (UO2)2+ are not observed in the Raman spectrum but may be readily observed in the infrared spectrum at 898 cm-1.  The v3 antisymmetric stretching mode of (CO3)2- is observed in the Raman spectrum at 1369 cm-1 as a low intensity band as is also the ν3 (CO3)2- infrared modes at 1362, 1425, 1509 and 1566 cm-1. No ν2 (CO3)2- Raman bending modes are observed for voglite. The Raman band at 749 cm-1 and the two infrared bands at 747 and 709 cm-1 are assigned to the ν4 (CO3)2- bending modes.  U-O bond and O-H…O bond lengths in the structure of voglite were inferred from the infrared and Raman spectra
Raman spectroscopy of smithsonite

Raman spectroscopy at both 298 and 77K has been used to study a series of selected natural smithsonites from different origins.  An intense sharp band at 1092 cm-1 is assigned to the CO32-  symmetric stretching vibration. Impurities of hydrozincite are identified by a band around 1060 cm-1. An additional band at 1088 cm-1 is observed in the 298 K spectra but not in the 77K spectra is attributed to a CO32- hot band. Raman spectra of smithsonite show a single band in the 1405 to 1409 cm-1 range assigned to the ν3 (CO3)2- antisymmetric stretching mode.  The observation of additional bands for the ν3g modes for some smithsonites is significant in that it shows distortion of the ZnO6 octahedron  No ν2 bending modes are observed for smithsonite. A single band at 730 cm-1 is assigned to the ν4 in phase bending mode.  Multiple bands be attributed to the structural distortion are observed for the carbonate ν4 in phase bending modes in the Raman spectrum of hydrozincite with bands at 733, 707 and 636 cm-1.  An intense band at 304 cm-1 is attributed to the ZnO symmetric stretching vibration
Synthesis and Raman spectroscopic characterisation of hydrotalcite with CO32- and (MoO4)2- anions in the interlayer

Raman spectroscopy has been used to characterise synthetic mixed carbonate and molybdate hydrotalcites of formula Mg6Al2(OH)16((CO3)2-,(MoO4)2-).4H2O. The spectra have been used to assess the molecular assembly of the cations and anions in the hydrotalcite structure. The spectra may be conveniently subdivided into spectral features based upon the carbonate anion, the molybdate anion, the hydroxyl units and water units. Bands are assigned to the hydroxyl stretching vibrations of water. Three types of carbonate anions are identified: (a) carbonate hydrogen-bonded to water in the interlayer, (b) carbonate hydrogen-bonded to the hydrotalcite hydroxyl surface, (c) free carbonate anions. It is proposed that the water is highly structured in the hydrotalcite as it is hydrogen bonded to both the carbonate and the hydroxyl surface. The spectra have been used to assess the contamination of carbonate in an open reaction vessel in the synthesis of a molybdate hydrotalcite of formula Mg6Al2(OH)16((CO3)2-,(MoO4)2-).4H2O. Bands are assigned to carbonate and molybdate anions in the Raman spectra. Importantly the synthesis of hydrotalcites from solutions containing molybdate provides a mechanism for the removal of this oxy-anion
Raman spectroscopic study of the uranyl phosphate minerals phosphuranylite and yingjiangite

Raman spectra of phosphuranylite and yingjiangite were measured, interpreted  and compared with published infrared spectra of both minerals. U-O bond lengths were calculated using the Bartlett-Cooney‘s empirical relations and the O-H-O hydrogen bond lengths were inferred on the basis of Libowitzky's empirical relation. The presence of oxonium and (H3O)+ ions, expected from the single crystal structure analysis of phosphuranylite, was not inferred from the Raman spectra. It was assumed that phosphuranylite and yingjiangite are identical and the name yingjiangite should be discarded because the name phosphuranylite has priority
Raman spectroscopic study of the uranyl carbonate mineral zellerite

Raman and infrared spectra of the uranyl mineral zellerite, Ca[(UO2)(CO3)2(H2O)2].3H2O, were measured and tentatively interpreted. U-O bond in uranyl and O-H…O hydrogen bonds were calculated from the vibrational spectra. The presence of structurally nonequivalent water molecules in the crystal structure of zellerite was inferred. Proposed chemical formula of zellerite is supported.  \ud
Raman bands at 3514, 3375 and 2945 cm-1 and broad infrared bands at 3513, 3396 and 3326 cm-1 are related to the vOH stretching vibrations of hydrogen bopnded water molecules. Observed wavenumbers of these vibrations prove that in fact hydrogen bonds participate in the crystal structure of zellerite. The presence of two bands at 1618 and 1681 cm-1 proves structurally distinct and nonequivalent water molecules in the crystal structure of zellerite
Raman and infrared spectroscopic study of the molybdate containing uranyl mineral calcurmolite

Raman and infrared spectra of calcurmolite were recorded and interpreted from the uranium and molybdenum polyhedra, water molecules and hydroxyls point of view. U-O bond lengths in uranyl and Mo-O bond lengths in MoO6 octahedra were calculated and O-H…O bond lengths were inferred from the spectra.   The mineral calcurmolite is characterised by bands assigned to the vibrations of the UO2 units. These units provide intense Raman bands at 930, 900 and 868 and 823 cm-1. These bands are attributed to the antisymmetric and symmetric stretching modes of the UO2 units respectively.  Raman bands at 794, 700, 644, 378 and 354 cm-1 are attributed to vibrations of the MoO4 units. The bands at 693 and 668 cm-1 are attributed to antisymmetric and symmetric Ag modes of terminal MO2 units.  Similar bands are observed at 797 and 773 cm-1 for koechlinite and 798 and 775 cm-1 for lindgrenite.   It is probable that some of the bands in the low wavenumber region are attributable to the bending modes of MO2 units
Synthesis and Raman spectroscopic characterisation of the oxalate mineral wheatleyite Na2Cu2+(C2O4)2.2H2O

The mineral wheatleyite was synthesised and characterised by Raman spectroscopy complimented with infrared spectroscopy.  Two Raman bands at 1434 and 1470 cm-1 are assigned to the ν(C-O) stretching mode and implies two independent oxalate anions. \ud
Two intense Raman bands observed at 904 and 860 cm-1 are assigned to the ν(C-C) stretching mode and support the concept of two non-equivalent oxalate units in the wheatleyite structure. Two strong bands observed at 565 and 585 cm-1 are assigned to the symmetric CCO in plane bending modes. The Raman band at 387 cm-1 is attributed to the CuO stretching vibration and the bands at 127 and 173 cm-1 to OCuO bending vibrations.  A comparison is made with Raman spectra of selected natural oxalate bearing minerals. Oxalates are markers or indicators of environmental events. Oxalates are readily determined by Raman spectroscopy. Thus deterioration of works of art, biogeochemical cycles, plant metal complexation, the presence of pigments and minerals formed in caves can be analysed
Raman spectroscopy of the nickel silicate mineral pecoraite –an anologue of chrysotile (asbestos)

The molecular structure of the mineral pecoraite, the nickel analogue of chrysotile of formula Ni3Si2O5(OH)4 has been analysed by a combination of Raman and infrared spectroscopy. A comparison is made with the spectra of the minerals nepouite and chrysotile and a synthetic pecoraite.  Pecoraite is characterised by OH stretching vibrations at 3645 and 3683 cm-1 attributed to the inner and inner surface hydroxyl stretching vibrations.  Intense infrared bands at around 3288 and 3425 cm-1 are assigned to the stretching vibrations of water strongly hydrogen bonded to the surface of the pecoraite.  The asbestos-like mineral is charactersied by SiO stretching vibrations at 979, 1075, 1128, 1384 cm-1, OSiO  chain vibrations at 616 and 761 cm-1 and  Ni-O(H) vibrations at 397 and 451 cm-1
Thermo-Raman spectroscopy of synthetic Nesquehonite – implication for the geosequestration of greenhouse gases

Pure nesquehonite (MgCO3.3H2O)/Mg(HCO3)(OH).2H2O was synthesised and characterised by a combination of thermo-Raman spectroscopy and thermogravimetry with evolved gas analysis.  Thermo-Raman spectroscopy shows an intense band at 1098 cm-1 which shifts to 1105 cm-1 at 450 degrees Celsius, assigned to the ν1 CO32- symmetric stretching mode. Two bands at 1419 and 1509 cm-1 assigned to the ν3 antisymmetric stretching mode shift to 1434 and 1504 cm-1 at 175 degrees Celsius.  Two new peaks at 1385 and 1405 cm-1 observed at temperatures higher than 175 degrees Celsius are assigned to the antisymmetric stretching modes of the (HCO3)- units. Throughout all the ThermoRaman spectra a band at 3550 cm-1 attributed to the stretching vibration of OH units. Raman bands at 3124, 3295, and 3423 are assigned to water stretching vibrations. The intensity of these bands is lost by 175 degrees Celsius.  The Raman spectra were in harmony with the thermal analysis data.  This research has defined the thermal stability of one of the hydrous carbonates namely nesquehonite. ThermoRaman spectroscopy enables the thermal stability of the mineral nesquehonite to be defined and further the changes in the formula of nesquehonite with temperature change can be defined.  Indeed Raman spectroscopy enables the formula of nesquehonite to be better defined as Mg(OH)(HCO3).2H2O
Raman spectroscopic study of the uranyl mineral compreignacite K2[(UO2)3O2(OH)3]2.7H2O

Raman spectra of the uranyl oxyhydroxy hydrated mineral compreignacite, K2[(UO2)3O2(OH)3]2.7H2O, were measured and interpreted. Observed bands were attributed to the stretching and bending vibrations of uranyl units, molecular water and hydroxyl ions. U-O bond lengths in uranyl and O-H…O hydrogen bond lengths were inferred from the spectra and compared with those from the X-ray single crystal structure data. The importance of this spectroscopic study rests with the ability to analyze very small amounts of mineral
Raman spectroscopy of hydroxy nickel carbonate minerals nullaginite and zaratite

Raman spectroscopy combined with infrared spectroscopy has been used to study the minerals, nullaginite and zaratite.  Raman bands are observed at 3650, 3556 and 3309 cm-1 for nullaginite and 3609, 3516 and 3336 cm-1 for zaraitite.  By using a Libowitzky type empirical function estimation of the hydrogen bond distances of the OH and water units has been made and values vary from 0.268nm to 0.332nm.  Hydrogen bond distances of OH units are less than for water units. The observation of multiple asymmetric stretching and bending modes for nullaginite suggests the carbonate is strongly distorted in contrast to zaratite for which only single bands are found. Raman bands at around 935 and 980 cm-1 are assigned to OH deformation modes