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Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy

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https://www.readbyqxmd.com/read/28941887/uv-vis-absorption-spectra-and-electronic-structure-of-merocyanines-in-the-gas-phase
#1
Alexander A Ishchenko, Andrii V Kulinich, Stanislav L Bondarev, Tamara F Raichenok
Gas-phase absorption spectra of a merocyanine vinylogous series have been studied for the first time. In vapour, their long-wavelength absorption bands were found to be considerably shifted hypsochromically, broader, more symmetrical, less intense, and their vinylene shift much smaller than even in low-polarity n-hexane. This indicates that in the gas phase their electronic structure closely approaches the nonpolar polyene limiting structure. The TDDFT calculations of the long-wavelength electronic transitions in the studied merocyanines in vacuo demonstrated good-to-excellent correlation - depending on the functional used - with the obtained experimental data...
September 21, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28941885/d-a-type-sensor-array-for-differentiation-and-identification-of-white-wine-varieties-based-on-specific-solvent-effect-activated-by-ct-le-transition
#2
Jingqi Han, Xin Zhang, Hao Li, Yue Hou, Jingdan Hou, Zhongfeng Li, Feng Yang, Yang Liu, Tianyu Han
In this work, we synthesize a series of compounds with electron donor (D) and acceptor (A) units. They show general solvent effect in aprotic solvents, suggesting a charge transfer (CT) process. While in protic solvents including water, ethanol and methanol, the spectra exert no polarity-dependence but a remarkable hypochromatic shift together with the fading of CT band. Dynamic analysis implies that intermolecular hydrogen bond will be formed between carboxylic acid and protic solvent, boosting another deactivation pathway that jumps off a bigger energy gap, in other words, favoring the locally excited (LE) state emission...
September 20, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28941413/surface-analysis-of-2-mercapto-1-methylimidazole-adsorbed-on-copper-by-x-ray-photoelectron-spectroscopy
#3
Matjaž Finšgar
A detailed analysis using X-ray photoelectron spectroscopy (XPS) is presented for the system of 2-mercapto-1-methylimidazole (MMeI) adsorbed on Cu in 3wt% NaCl solution. High-resolution and survey XPS spectra and XPS-excited Auger L3M4,5M4,5 spectra were analysed in detail. Surface analysis revealed that the MMeI molecules do not lie flat on the surface via π-d interactions, but adsorb on the surface through an N-S-bridge configuration. Moreover, the characteristic Cu(I)-MMeI connection fingerprint, which is usually observed for these kinds of molecules, was not observed...
September 19, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28941886/spectroscopic-and-theoretical-investigations-on-intramolecular-charge-transfer-phenomenon-in-1-3-dioxolane-derivative
#4
Zhiyong Zhang, Zhongzhi Zhang, Yijing Luo, Shanshan Sun, Guangqing Zhang
No abstract text is available yet for this article.
September 18, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28938168/energy-transfer-and-color-tunable-emission-in-tb-3-eu-3-co-doped-sr3lana-po4-3f-phosphors
#5
Shuo Li, Ning Guo, Qimeng Liang, Yu Ding, Huitao Zhou, Ruizhuo Ouyang, Wei Lü
A group of color tunable Sr3LaNa(PO4)3F:Tb(3+),Eu(3+) phosphors were prepared by conventional high temperature solid state method. The phase structures, luminescence properties, fluorescence lifetimes and energy transfer were investigated in detail. Under 369nm excitation, owing to efficient energy transfer of Tb(3+)→Eu(3+), the emission spectra both have green emission of Tb(3+) and red emission of Eu(3+). An efficient energy transfer occur in Tb(3+), Eu(3+) co-doped Sr3LaNa(PO4)3F phosphors. The most possible mechanism of energy transfer is dipole-dipole interaction by Dexter's theoretical model...
September 18, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28934701/hydrothermal-synthesis-of-4zno%C3%A2-b2o3%C3%A2-h2o-ln-3-ln-eu-tb-phosphors-morphology-tunable-and-luminescence-properties
#6
Shiwei Cao, Yang Jiao, Weifang Han, Chunhua Ge, Bo Song, Jie Wang, Xiangdong Zhang
4ZnO·B2O3·H2O:Ln(3+) (Ln=Eu, Tb) phosphors with different morphologies have been successfully synthesized via one-step hydrothermal method through regulating the molar amount of Eu(3+) and Tb(3+). Comprehensive scanning electron microscopy (SEM), X-ray diffraction (XRD) Fourier transform infrared spectrum (FT-IR) and inductively coupled plasma atomic emission spectrometer (ICP-AES) characterizations all confirm that obtained products are 4ZnO·B2O3·H2O:Ln(3+) (Ln=Eu, Tb). The experimental results displayed that the morphology and photoluminescence of compounds is regularly changed with increased the molar amount of rare earth ions...
September 18, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28934700/copper-ii-complex-with-6-methylpyridine-2-carboxyclic-acid-experimental-and-computational-study-on-the-xrd-ft-ir-and-uv-vis-spectra-refractive-index-band-gap-and-nlo-parameters
#7
Sümeyye Altürk, Davut Avcı, Adil Başoğlu, Ömer Tamer, Yusuf Atalay, Necmi Dege
Crystal structure of the synthesized copper(II) complex with 6-methylpyridine-2-carboxylic acid, [Cu(6-Mepic)2·H2O]·H2O, was determined by XRD, FT-IR and UV-Vis spectroscopic techniques. Furthermore, the geometry optimization, harmonic vibration frequencies for the Cu(II) complex were carried out by using Density Functional Theory calculations with HSEh1PBE/6-311G(d,p)/LanL2DZ level. Electronic absorption wavelengths were obtained by using TD-DFT/HSEh1PBE/6-311G(d,p)/LanL2DZ level with CPCM model and major contributions were determined via Swizard/Chemissian program...
September 18, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28938170/aromatic-hydrazones-derived-from-nicotinic-acid-hydrazide-as-fluorimetric-ph-sensing-molecules-structural-analysis-by-computational-and-spectroscopic-methods-in-solid-phase-and-in-solution
#8
T Benković, A Kenđel, J Parlov-Vuković, D Kontrec, V Chiş, S Miljanić, N Galić
Structural analyses of aroylhydrazones were performed by computational and spectroscopic methods (solid state NMR, 1 and 2D NMR spectroscopy, FT-IR (ATR) spectroscopy, Raman spectroscopy, UV-Vis spectrometry and spectrofluorimetry) in solid state and in solution. The studied compounds were N'-(2,3-dihydroxyphenylmethylidene)-3-pyridinecarbohydrazide (1), N'-(2,5-dihydroxyphenylmethylidene)-3-pyridinecarbohydrazide (2), N'-(3-chloro-2-hydroxy-phenylmethylidene)-3-pyridinecarbohydrazide (3), and N'-(2-hydroxy-4-methoxyphenyl-methylidene)-3-pyridinecarbohydrazide (4)...
September 15, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28922637/optical-activity-of-co-porphyrin-in-the-light-of-ir-and-raman-spectroscopy-a-critical-dft-investigation
#9
Debesh R Roy, Esha V Shah, Sutapa Mondal Roy
A critical investigation on the structure, electronic properties and optical activities of a series of transition metal doped porphyrins (TMP; TM=Fe, Co, Ni) in the light of infrared and Raman spectroscopy is performed, under density functional formalism. The structure and electronic properties are studied in terms of ionization potential, electron affinity, chemical hardness (η), binding energies of the transition metals (BETM) etc. The origin of the optical activities, especially the visibly active cobalt porphyrin is addressed through critical study on their infrared and Raman spectra...
September 15, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28941414/synthesis-spectral-and-luminescence-study-crystal-structure-determination-and-dft-calculation-of-binuclear-palladium-ii-complexes
#10
S Seyfi, R Alizadeh, M Darvish Ganji, V Amani
Binuclear palladium(II) complexes with metal-metal (d(8)-d(8)) bonding interaction were synthesized by reactions of the 1-methyl-1H-1,2,3,4-tetrazole-5-thiol (Hmtzt) or a mixture of Hmtzt and 1,3-propanediamine (1,3-pda) ligands. Complex [Pd2(μ-mtzt)4]·2CH3CN (1) was synthesized by the reaction of Pd(OAc)2 with Hmtzt dissolved in acetonitrile and complex [Pd2(μ-mtzt)2(mtzt)2(1,3-pda)] (2) was synthesized by reaction of a mixture of Hmtzt and 1,3-propanediamine (dissolved in methanol) with PdCl2 (dissolved in acetonitrile) and were identified through elemental analysis, IR, UV-Vis, (1)H NMR, luminescence spectroscopy as well as single-crystal X-ray diffraction method...
September 14, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28938169/effect-of-nitrogen-plasma-afterglow-on-the-1000-1800-cm-1-band-in-ft-ir-spectra-of-amorphous-carbon-nitride-thin-films
#11
Kamal Kayed
The aim of this paper is to develop the understanding of the mechanism which explains the formation of the (1000-1800) cm(-1) band in FT-IR spectra of amorphous carbon nitride thin films prepared by laser ablation method. The study results show that the bonds C(sp(3))N is have significant role in the formation of the (1000-1800) cm(-1) band, and it is necessary to provide a minimum amount of these bonds to be able to contribute in breaking the symmetry of the sp(2) carbon bonds.
September 14, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28934699/pseudopotential-calculations-of-alsb-under-pressure
#12
H Algarni, O A Al-Hagan, N Bouarissa, M A Khan, T F Alhuwaymel
The dependence on hydrostatic pressure of the electronic and optical properties of zinc-blende AlSb semiconducting material in the pressure range of 0-20kbar has been reported using a pseudopotential approach. At zero pressure, our findings showed that the electron and heavy hole effective masses are 0.11 and 0.38m0, respectively. Moreover, our results yielded values of 3.3289 and 11.08 for refractive index and high frequency dielectric constant, respectively. These results are found to be in good accord with experiment...
September 14, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28926771/a-new-low-temperature-solid-modification-in-1-isothiocyanato-4-trans%C3%A2-4-propylcyclohexyl-benzene-3chbt-probed-by-raman-spectroscopy-and-quantum-chemical-calculations
#13
K Vikram, Ranjan K Singh, Satyendra Nath Gupta
Raman spectra of 1-isothiocyanato-4-(trans 4-propylcyclohexyl)benzene (3CHBT) were studied in the region, 1450-2300cm(-1) at twenty two different temperatures in the range, 83-293K in cooling and heating cycles. All bands in this region were critically evaluated in term of linewidth, peak position and relative intensity. Raman bands at ~2085cm(-1) and ~2120cm(-1) shows clear evidence of a solid modification through anomaly in temperature dependence peak positions and linewidths variation in the temperature range 173-203K...
September 14, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28922639/synthesis-and-characterization-of-8-hydroxyquinolin-1-ium-2-2-2-trifluoroacetate-and-8-hydroxyquinolin-1-ium-2-2-2-trichloroacetate-by-z-scan-technique
#14
M D Zidan, A Arfan, A Allahham
The 8-hydroxyquinolin-1-ium 2,2,2-trifluoroacetate and 8-hydroxyquinolin-1-ium 2,2,2-trichloroacetate (8-HQ) salts have been synthesized and characterized by FTIR, NMR and UV-Vis absorption spectroscopic methods. The third order nonlinear optical properties (NLO) of the two 8-HQ salts have been investigated by z-scan technique. The recorded experimental data led to calculate the nonlinear optical absorption coefficient (β), the nonlinear refractive index (n2), the excited-state absorption cross section (σex) and the ground-state absorption cross section (σg) of the studied compounds...
September 14, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28918219/a-highly-selective-fluorescent-chemosensor-for-cn-based-on-a-novel-bis-salamo-type-tetraoxime-ligand
#15
Fei Wang, Lei Gao, Qing Zhao, Yang Zhang, Wen-Kui Dong, Yu-Jie Ding
The optical properties of a novel chemosensor for cyanide anions based on a symmetric bis(salamo)-type ligand (H3L) were investigated by UV-Vis and fluorescence spectroscopy in MeOH/H2O (1:1 v/v) solution. Sensor H3L can selectively sense CN(-) based on prominent color changes among other anions. The chemosensor exhibits an apparent fluorescence enhancement at 482nm to CN(-) which because cyanide ions interact with CN bonds. Combining the corrected Benesi-Hildebrand formula, the binding constant of the formed host-guest complex was calculated as 2...
September 14, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28941884/cooperative-upconversion-luminescence-of-er-3-in-gd2o3-xsx-phosphor
#16
Fei Wang, Bin Yang, Qingchun Yu, Dachun Liu, Wenhui Ma
Gd2O3-xSx:Er crystals were prepared through high-temperature solid-state reaction method in vacuum, with the vacuum synthesis mechanism determined by thermal analysis. The crystal structure and upconversion luminescence properties were investigated respectively by XRD, TEM and spectrophotometer. Well crystallized Gd2O2S:Er phosphors were prepared under 1000°C in vacuum with a certain excessive amount of sulfur content than stoichiometric. It is confirmed that with the increasing sulfur content the green emission was enhanced and red emission was weakened...
September 13, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28941412/rapid-determination-of-crocins-in-saffron-by-near-infrared-spectroscopy-combined-with-chemometric-techniques
#17
REVIEW
Shuailing Li, Qingsong Shao, Zhonghua Lu, Chengli Duan, Haojun Yi, Liyang Su
Saffron is an expensive spice. Its primary effective constituents are crocin I and II, and the contents of these compounds directly affect the quality and commercial value of saffron. In this study, near-infrared spectroscopy was combined with chemometric techniques for the determination of crocin I and II in saffron. Partial least squares regression models were built for the quantification of crocin I and II. By comparing different spectral ranges and spectral pretreatment methods (no pretreatment, vector normalization, subtract a straight line, multiplicative scatter correction, minimum-maximum normalization, eliminate the constant offset, first derivative, and second derivative), optimum models were developed...
September 13, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28934702/effect-of-methyl-substituents-on-the-electronic-transitions-in-simple-meso-aniline-bodipy-based-dyes-ri-cc2-and-td-cam-b3lyp-computational-investigation
#18
Igor K Petrushenko, Konstantin B Petrushenko
The S0→Si, i=1-5 electronic transitions of four 8-(4-aniline)-BODIPY and four 8-(N,N-dimethyl)-BODIPY dyes, differ by number and position of methyl substituents in the BODIPY frame, were investigated theoretically using ab initio the coupled cluster doubles (CC2) and TD-CAM-B3LYP methods. Methyl substituents in the BODIPY frame and the aniline fragment at the meso position disturb energy of local excitations S0→S1, S0→S3, and S0→S4 weakly in comparison with the fully unsubstituted BODIPY molecule. These transitions in experimental spectra form the most long-wave absorption bands at ca...
September 13, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28926772/ultrasound-assisted-interaction-between-chlorin-e6-and-human-serum-albumin-ph-dependence-singlet-oxygen-production-and-formulation-effect
#19
Mihaela N Mocanu, Fei Yan
The interaction between chlorin e6 (Ce6) and human serum albumin (HSA) in the presence and absence of ultrasound have been investigated by ultraviolet-visible absorption spectroscopy and fluorescence spectroscopy. Ce6 is found to bind strongly to HSA at or near physiological pH conditions, but the strength of the binding is significantly weakened at lower pHs. The intrinsic fluorescence of HSA is incrementally quenched with increasing concentration of Ce6, and the quenching is enhanced after exposure to high-frequency ultrasound...
September 13, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28922646/synthesis-spectral-characterization-and-computed-optical-analysis-of-potent-triazole-based-compounds
#20
Sajjad H Sumrra, Fazila Mushtaq, Muhammad Khalid, Muhammad Asam Raza, Muhammad Faizan Nazar, Bakhat Ali, Ataualpa A C Braga
Biologically active triazole Schiff base ligand (L) and metal complexes [Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)] are reported herein. The ligand acted as tridentate and coordinated towards metallic ions via azomethine-N, triazolic-N moiety and deprotonated-O of phenyl substituents in an octahedral manner. These compounds were characterized by physical, spectral and analytical analysis. The synthesized ligand and metal complexes were screened for antibacterial pathogens against Chromohalobacter salexigens, Chromohalobacter israelensi, Halomonas halofila and Halomonas salina, antifungal bioassay against Aspergillus niger and Aspergellus flavin, antioxidant (DPPH, phosphomolybdate) and also for enzyme inhibition [butyrylcholinesterase (BChE) and acetylcholinesterase (AChE)] studies...
September 13, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
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