scholarly journals Spectroscopic Analysis for Harnessing the Quality and Potential of Gemstones for Small and Medium-Sized Enterprises (SMEs)

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Imtiaz Ahmad ◽  
Suhail H. Serbaya ◽  
Ali Rizwan ◽  
Malik Sajjad Mehmood
Keyword(s):  
Spectroscopic Analysis ◽  
Structural Disorder ◽  
Quality Analysis ◽  
Spectroscopic Techniques ◽  
Bending Vibrations ◽  
Medium Development ◽  
Strategic Initiatives ◽  
Stretching Vibration ◽  
Stretching Vibrations ◽  
Modern Technologies

Introduction of modern technologies and methods and quality analysis for the gemstone industry are the main strategic initiatives of the Small and Medium Development Authority (SMEDA) of Pakistan. In this regard, four natural gemstones Quartz, Pyrope-Almandine Garnet, Black tourmaline, and Amethyst brought from Hunza valley Pakistan were analyzed by state-of-the-art spectroscopic techniques including EDX, UV-VIS, and FTIR spectroscopy. EDX revealed the traces of Fe, Mg, and Ca in Pyrope-Almandine garnet, Mg and Fe in Black tourmaline, Au and Ca in Amethyst. UV-VIS data revealed the values of Urbach energies 520, 210, 460, and 430 meV, and the values of direct bandgap energies 5.14, 6.12, 5.54, 5.74 eV, respectively. The higher structural disorder due to the presence of Fe and other impurities in stones except Quartz was attributed to the higher values of Urbach energies and decrease in band gaps: FTIR data Fe-O and Si-O stretching vibration in Pyrope-Almandine garnet, Si-O bending vibrations and O-H stretching vibration in Quartz, Si-O-Si bending and stretching vibrations and C=O stretching vibrations in Black tourmaline, Ca-O stretching vibrations and Si-OH weak-vibrations in Amethyst. Photoluminescence results also showed useful information in investigating the properties of gemstones.

Infrared spectra and substituent effects in 2-(3-, and 4-substituted phenylmethylene)-1,3-cycloheptanediones

1983 ◽  
Vol 48 (2) ◽  
pp. 586-595 ◽  
Author(s):  
Alexander Perjéssy ◽  
Pavol Hrnčiar ◽  
Ján Šraga
Keyword(s):  
Substituent Effects ◽  
Phenyl Group ◽  
Wave Number ◽  
Vibrational Coupling ◽  
Wave Numbers ◽  
Stretching Vibration ◽  
Stretching Vibrations ◽  
The Relationship ◽  
Derivatives Of ◽  
Effect Of Structure

The wave numbers of the fundamental C=O and C=C stretching vibrations, as well as that of the first overtone of C=O stretching vibration of 2-(3-, and 4-substituted phenylmethylene)-1,3-cycloheptanediones and 1,3-cycloheptanedione were measured in tetrachloromethane and chloroform. The spectral data were correlated with σ+ constants of substituents attached to phenyl group and with wave number shifts of the C=O stretching vibration of substituted acetophenones. The slope of the linear dependence ν vs ν+ of the C=C stretching vibration of the ethylenic group was found to be more than two times higher than that of the analogous correlation of the C=O stretching vibration. Positive values of anharmonicity for asymmetric C=O stretching vibration can be considered as an evidence of the vibrational coupling in a cyclic 1,3-dicarbonyl system similarly, as with derivatives of 1,3-indanedione. The relationship between the wave numbers of the symmetric and asymmetric C=O stretching vibrations indicates that the effect of structure upon both vibrations is symmetric. The vibrational coupling in 1,3-cycloheptanediones and the application of Seth-Paul-Van-Duyse equation is discussed in relation to analogous results obtained for other cyclic 1,3-dicarbonyl compounds.

Silver Nanoparticles Included Er3+/Sm3+ Co-Doped Phosphate Glass: Evaluation of Thermal Stability and Infrared Absorption

2017 ◽  
Vol 268 ◽  
pp. 62-66 ◽  
Author(s):  
S. Rashidah Misron ◽  
Ramli Arifin ◽  
Sib Krishna Ghoshal
Keyword(s):  
Thermal Stability ◽  
Phosphate Glass ◽  
Infrared Absorption ◽  
Glass Network ◽  
Ir Absorption ◽  
Ag Nps ◽  
Bending Vibrations ◽  
Host Matrix ◽  
Stretching Vibrations ◽  
Quenching Method

Three lithium-sodium-phosphate glass samples with molar composition of (48.5–x)P2O5-20Na2O-30Li2O-0.5Sm2O3-1.0Er2O3-xAgNPs (where x = 0.01 g, 0.03 g and 0.05 g) are prepared using melt quenching method. The thermal stability and infrared absorption of synthesized samples are evaluated as a function of Ag NPs contents. Thermal and structural characterizations are made using differential thermal analysis (DTA) and Fourier transformed infrared (FTIR) spectroscopy, respectively. Thermal stability is found to vary in the range of 171 °C to 197 °C. FTIR spectra revealed various characteristic bonding vibrations related to the glass network structures. The IR absorption band around 570 cm-1 is assigned to the P-O-P bending vibrations while the occurrence of bands around 759 cm-1 and 913 cm-1 are allocated to the P-O-P symmetric stretching vibrations. The asymmetric stretching vibrations of (PO3)2- and (PO2)- units are observed around 1045 cm-1 and 1254 cm-1 , respectively. The appearance of a band around 1735 cm-1 is allocated to the free H2O molecules because of moisture attack to the sample. Influences of Ag NPs in the host matrix are analyzed and explained.

scholarly journals Distinguishing Features and Identification Criteria for K-Dioctahedral 1M Micas (Illite-Aluminoceladonite and Illite-Glauconite-Celadonite Series) from Middle-Infrared Spectroscopy Data

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 153 ◽  
Author(s):  
Bella B. Zviagina ◽  
Victor A. Drits ◽  
Olga V. Dorzhieva
Keyword(s):  
Infrared Region ◽  
Spectroscopy Data ◽  
Unit Cell Parameters ◽  
Cation Composition ◽  
Cell Parameters ◽  
Sharp Maximum ◽  
Stretching Vibration ◽  
Stretching Vibrations ◽  
Middle Infrared ◽  
Distinguishing Features

A representative collection of K-dioctahedral 1M micas ranging in composition from (Mg, Fe)-poor illites to aluminoceladonites through Mg-rich illites (Fe-poor varieties) and from Fe-bearing, Mg-rich illites to celadonites through Fe-illites, Al-glauconites and glauconites (Fe-bearing varieties) was studied by Fourier-transform infrared (FTIR) spectroscopy in the middle-infrared region. Analysis and comparison of the relationships between the band positions and cation compositions of Fe-poor and Fe-bearing K-dioctahedral micas provided a generalized set of FTIR identification criteria that include the band positions and profiles in the regions of Si–O bending, Si–O stretching, and OH-stretching vibrations. FTIR data allow unambiguous identification of illites, aluminoceladonites, and celadonites, as well as distinction between Fe-illites and illites proper, as well as between Al-glauconites and glauconites. Specifically, a sharp maximum from the AlOHMg stretching vibration at ~3600 cm−1, the presence of a MgOHMg stretching vibration at 3583–3585 cm−1, as well as characteristic band positions in the Si–O bending (435–439, 468–472 and 509–520 cm−1) and stretching regions (985–1012 and 1090–1112 cm−1) are clearly indicative of aluminoceladonite. The distinction between Fe-illites and Al-glauconites, which have similar FTIR features, requires data on cation composition and unit-cell parameters.

Die Schwingungsfeinstruktur der Elektronenspektren des 13C- und 18O-markierten trans-Dioxotetracyanoosmats (VI),[OsO2(CN)4]2 -

1988 ◽  
Vol 43 (3) ◽  
pp. 239-247 ◽  
Author(s):  
C. Sartori ◽  
W. Preetz
Keyword(s):  
Ground State ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Isotopic Shifts ◽  
Charge Transfer Transitions ◽  
Stretching Vibration ◽  
Stretching Vibrations ◽  
The One ◽  
Franck Condon ◽  
Electronic Ground

The electronic absorption spectrum of the solid tetramethyl-ammonium salt of [OsO2(CN)4]2 - is measured at 10 K. The five distinct band systems exhibit vibrational progressions in the range 660-750 cm - 1, corresponding to the Os = O stretching vibrations sometimes coupled with ν(OsC). From this vibrational fine structure the electronic origin is deduced and verified by characteristic isotopic shifts by 18O and 13C. The two bands at lowest energy are assigned to the d-d-transitions 1A1g [b22g] → 3Eg [b12g e1g] (620 - 460 nm) and 1A1g [b22g] → 1Eg [b12g e1g] (490 - 400 nm). The 3Eg state is split by spin-orbit coupling into 5 components, from the one at lowest energy a luminescence emission (830 - 670 nm) takes place with a progression of 860 cm-1, corresponding to the symmetric Os = O stretching vibration in the electronic ground state. The more intense bands are assigned to charge transfer transitions from oxo π-orbitals into unoccupied niveaus of Os (VI): 1A1g [e4u] → 3A2u [e3u e1g] (390 - 340); → 1A1u [e3u e1g] (340 - 290) and → 1Eu [e3u b11g (290 - 230 nm). The singlet-triplet distances are 3200-3600 cm - 1. From a Franck-Condon analysis an excited state elongation of 10-13 pm for the osmyl groups is calculated.

Breeding for robust cows that produce healthier milk: RobustMilk

2013 ◽  
Vol 4 (3) ◽  
pp. 594-599 ◽  
Author(s):  
R. F. Veerkamp ◽  
L. Kaal ◽  
Y. de Haas ◽  
J. D. Oldham
Keyword(s):  
Natural Variation ◽  
Spectroscopic Analysis ◽  
Production Systems ◽  
Milk Quality ◽  
Quality Analysis ◽  
Mid Infrared ◽  
Livestock Species ◽  
The Core ◽  
Genomic Tools ◽  
Selection For

For centuries, animal breeders have very effectively been selecting livestock species, making use of the natural variation that exists within the population. As part of the developments towards broader breeding goals, the RobustMilk project was designed to develop new practical technologies to allow breeders to re-focus their selection to include milk quality and dairy cow robustness and to evaluate the consequences of selection for these traits taking cognisance of various milk production systems. Here we introduce the background to robustness, the value of expanding milk quality analysis (including the possibility of using milk quality characteristics as proxy measures for robustness traits), interactions between robustness and milk quality traits and the need for different breeding tools to enable delivery of these concepts to the industry. Developing a database with phenotypes from research herds across Europe, phenotyping tools using mid-infrared red spectroscopic analysis of milk, and the development of statistical and genomic tools for robustness and milk quality formed the core of the project. In the following papers you will read the outcomes and developments that happened during the project.

Theoretical Modeling of the N-H and N-D Stretching Bands of Hydrogen-Bonded 1-Methylthymine Crystal and Its Deuterated Form

2006 ◽  
Vol 2 (4) ◽  
pp. 205-219
Author(s):  
Marek Boczar ◽  
Łukasz Boda ◽  
Marek J. Wójcik
Keyword(s):  
Hydrogen Bonds ◽  
High Frequency ◽  
Molecular Crystals ◽  
Low Frequency ◽  
Unit Cell ◽  
Fermi Resonance ◽  
Bending Vibrations ◽  
Theoretical Simulation ◽  
Stretching Vibrations ◽  
Centrosymmetric Dimers

Theoretical model for vibrational interactions in the hydrogen bonds in molecular crystals with four molecules forming two centrosymmetric dimers in the unit cell is presented. The model takes into account anharmonic-type couplings between the high-frequency N-H(D) and the low-frequency N•••O stretching vibrations in each hydrogen bond, resonance interactions (Davydov coupling) between equivalent hydrogen bonds in each dimer, resonance interdimer interactions within an unit cell and Fermi resonance between the N-H(D) stretching fundamental and the first overtone of the N-H(D) in-plane bending vibrations. The vibrational Hamiltonian, selection rules, and expressions for the integral properties of an absorption spectrum are derived. The model is used for theoretical simulation of the νs stretching bands of 1-methylthymine and its ND derivative at 300 K. The effect of deuteration is successfully reproduced by our model.

Vibrational band intensities in substituted anilines

1957 ◽  
Vol 243 (1233) ◽  
pp. 143-153 ◽  
Keyword(s):  
Linear Relation ◽  
Vibrational Band ◽  
Vibration Band ◽  
Substituted Anilines ◽  
Absorption Bands ◽  
Bond Stretching ◽  
Infra Red ◽  
Analogous Data ◽  
Stretching Vibration ◽  
Stretching Vibrations

The infra-red absorption bands associated with the stretching vibrations of the NH 2 group in a series of meta - and para -substituted anilines have been examined. The effect of the sub­stituet groups upon the frequencies and intensities of the bands has been correlated with their Hammett σ factors. The widths of the bands have also been found to depend upon the position and nature of substituent. The linear relation between log (intensity) and σ suggested previously on the basis of other data has been found to hold in this case too. Measurements in several solvents have been compared, and surprising variations of band intensity have been found. Analogous data have been obtained for the N—H bond stretching vibration band in substituted N -methyl anilines. The effect of ortho substituents has also been examined in a few cases.

Infrared Studies of the Isomerization of Cis-Pd(NH3)2X2

1967 ◽  
Vol 21 (4) ◽  
pp. 221-224 ◽  
Author(s):  
J. R. Durig ◽  
B. R. Mitchell
Keyword(s):  
Reaction Mechanism ◽  
Trans Isomer ◽  
Room Temperature ◽  
Palladium Complexes ◽  
Trans Isomers ◽  
First Order ◽  
Infrared Studies ◽  
Intensity Changes ◽  
Stretching Vibration ◽  
Stretching Vibrations

Palladium complexes of the type cis-PdL2X2 have been found to be unstable at room temperature and isomerize to the corresponding trans isomers. Neglecting lattice interactions, symmetry considerations would predict two Pd–N stretching vibrations. These vibrations have been observed at 495 and 476 cm−1 for the cis-chloride isomer and at 480 and 460 cm−1 for the cis-bromide isomer. The trans isomer, by the same considerations, should have but one Pd–N stretching vibration. This vibration was observed for the trans-chloride isomer at 496 cm−1 and for the trans-bromide isomer at 490 cm−1. It has been found that as isomerization proceeds, from the cis to the trans forms, the lower Pd–N stretching vibration decreases in intensity and eventually disappears. The intensity changes for these vibrations over a period of 72 h indicated that the reaction follows a first-order rate law. A reaction mechanism has been proposed.

Infrared spectra and hydrogen bonding in some methyl α-glycopyranosides

1975 ◽  
Vol 28 (2) ◽  
pp. 335 ◽  
Author(s):  
AJ Michell
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Infrared Spectra ◽  
Bending Vibrations ◽  
Ambient Temperatures ◽  
Out Of Plane ◽  
Stretching Vibrations ◽  
Plane Bending

Spectra in the OH stretching and out-of-plane bending regions of four methyl α-glycopyranosides of known crystal structure have been obtained at ambient and sub-ambient temperatures. Partial deuteration has been used to uncouple the stretching vibrations and assist in assignments of the out-of-plane bending vibrations.

Efficient Detection of Extra Virgin Olive Oil Adulteration via UV and FTIR Spectra in combination with Heat-Mediated Oxidation Method

2021 ◽  
Author(s):  
Sepideh Gholami Khesht ◽  
E Kavusi ◽  
M Mousavi
Keyword(s):  
Olive Oil ◽  
Virgin Olive Oil ◽  
Extra Virgin Olive Oil ◽  
Peak Position ◽  
Uv Spectra ◽  
Ftir Spectra ◽  
Spectroscopic Techniques ◽  
Chemical Waste ◽  
Bending Vibrations ◽  
Efficient Detection

The main aim of this study is simple and fast authentication of extra virgin olive oil by different spectroscopic techniques individually and also in combination with minimal chemical waste. UV spectra of the EVOO and mixed olive oil samples were recorded before the heating test and then along the thermal degradation experiments at the 45- and 90-mins intervals set for the analysis.  The EVOO and mixed oils samples showed high absorption values around 240-300 nm band. The results showed that the characteristics of FTIR spectra including peak number, peak position and peak shape in mixed samples were significantly different from EVOO samples. According to the studies, the frequencies of around 2920 cm−1 and 2856 cm−1 could be related with C–H stretching (e.g. cis-double bonds) and with –C–H asymmetrical and symmetrical stretching in methylene groups. The frequency at 2925 cm−1 is associated with aliphatic CH2 groups. Around 1366 cm−1 and 1451 cm−1, these frequencies could be associated with the bending vibrations of C–H groups. The results reveal that the UV–VIS and FT-IR analytical tools are the most suitable and reliable tools to detect and quantify high levels (over 10%) of adulteration in mixes of EVO with other vegetable oils.

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