scholarly journals Toward Engineering Intrinsic Line Widths and Line Broadening in Perovskite Nanoplatelets

ACS Nano ◽  
2021 ◽  
Vol 15 (4) ◽  
pp. 6499-6506
Author(s):  
Albert Liu ◽  
Gabriel Nagamine ◽  
Luiz G. Bonato ◽  
Diogo B. Almeida ◽  
Luiz F. Zagonel ◽  
...  
Keyword(s):  
Line Broadening ◽  
Line Widths

Nuclear magnetic resonance spectroscopy of denatured proteins

1969 ◽  
Vol 22 (5) ◽  
pp. 1083 ◽  
Author(s):  
JH Bradbury ◽  
NLR King
Keyword(s):  
Molecular Weight ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Trifluoroacetic Acid ◽  
Guanidine Hydrochloride ◽  
Dichloroacetic Acid ◽  
Random Coil ◽  
Resonance Spectroscopy ◽  
Line Broadening ◽  
Line Widths

The proton magnetic resonance spectroscopy of 11 proteins (molecular weight range 5700-650000) has been investigated in five denaturing solvents, viz., trifluoroacetic acid-d, formic acid, dichloroacetic acid, 6M guanidine hydrochloride in D2O, and 8M urea in D2O. The chemical shifts, line-widths, and intensities of the resonances have been measured of the histidine C2 protons, the methionine SCH3 protons and methyl protons of leucine, isoleucine, and valine, the aromatic protons, and the α-CH protons. ��� It is found that, with some exceptions delineated below, the line- widths of the methyl resonances are constant for a particular solvent, independent of the molecular weight of the protein. This indicates that, in general, the proteins behave as random coil structures in these solvents, which confirms the conclusion reached by Tanford and co-workers1-4 for 6M guanidine hydrochloride. ��� However, methyl line broadening occurs in dichloroacetic acid for catalase and fibrinogen, in guanidine hydrochloride for insulin, and in urea for insulin and lysozyme. Furthermore, the C 2 histidine resonance is absent in dichloroacetic acid solutions of thyroglobulin, catalase, and fibrinogen; the SCH3 resonance is absent in myoglobin in trifluoroacetic acid-d and occurs as a doublet for trypsin in guanidine hydrochloride and in urea. A general line broadening of resonances indicates association and/or incomplete unfolding of molecules, whereas perturbations of only one particular resonance, as in the cases detailed above, are probably due to intramolecular non-covalent interactions which involve the perturbed group and another unspecified group in the protein. ��

scholarly journals Line Broadening Data: Stark Broadening of Ca II Sc III And Ti IV Lines

1993 ◽  
Vol 137 ◽  
pp. 260-262
Author(s):  
Milan S. Dimitrijević ◽  
Sylvie Sahal-Bréchot
Keyword(s):  
Stark Broadening ◽  
Isoelectronic Sequence ◽  
Line Broadening ◽  
Proton Impact ◽  
Line Widths ◽  
And Shifts

AbstractElectron– and proton–impact line widths and shifts for important Ca II, Sc III and Ti IV lines, have been calculated using the semiclassical–perturbation formalism. The obtained results were used to investigate the behaviour of Stark broadening parameters within the K I isoelectronic sequence.

N.M.R. spectra of the carbolines. II. 14N quadrupolar and exchange broadening of spectral lines

1973 ◽  
Vol 26 (7) ◽  
pp. 1523 ◽  
Author(s):  
F Balkau ◽  
ML Heffernan
Keyword(s):  
Pyridine Ring ◽  
Chemical Exchange ◽  
Spectral Lines ◽  
Line Broadening ◽  
Quadrupolar Relaxation ◽  
Line Widths ◽  
Exchange Broadening

The n.m.r, spectra of carbazole and the carbolines were previously reported to show unusual line broadening effects under certain conditions. It is found that for the proton in position 9 both chemical exchange and 14N quadrupolar relaxation are responsible for the large line widths observed, while for protons in the ?pyridine? ring chemical exchange is the more important effect. The nature of this exchange is still uncertain, the rate being critically dependent on solvent and sample purity as well as temperature.

scholarly journals Line broadening of SO2 and CO2 volcanic activity gases in the Earth’s atmosphere

2018 ◽  
Vol 62 ◽  
pp. 02010
Author(s):  
Anna S. Dudaryonok ◽  
Nina N. Lavrentieva ◽  
Nikolai A. Lavrentiev
Keyword(s):  
Carbon Dioxide ◽  
Quantum Number ◽  
Room Temperature ◽  
Rotational Quantum Number ◽  
Energy Difference ◽  
Empirical Method ◽  
Line Broadening ◽  
Wide Range ◽  
Line Widths ◽  
Semi Empirical

Calculations of the CO2-broadening coefficients of sulfur oxide lines by the semi-empirical method [Mol. Phys. 102 (2004) 1653] and averaged energy difference method [Atmosph. Ocean. Optics 28 (2015) 403] are presented. In this work, 41 lines are considered, the rotational quantum number J varies from 14 to 51. Calculations of the line widths are carried out for room temperature (296 K), and also for the temperature range typical for the Ears atmosphere. There is good agreement with the literature data. The carbon dioxide lines broadening coefficients induced by nitrogen, nitrogen oxide, carbon monoxide and carbon dioxide at room temperature (T = 296 K) are obtained for a wide range of the rotational quantum number J (up to 100). The temperature exponents are calculated for every line widths. The calculations were performed by a semi-empirical method, based on the semiclassical impact theory of line broadening and modified by introducing additional correction factor whose parameters can be determined by fitting the broadening or shifting coefficients to the experimental data.

Nondestructive Inspection of Thin, Low-Z Samples using Multiplexed Compton Scatter Tomography

1997 ◽  
Vol 503 ◽  
Author(s):  
B. L. Evans ◽  
J. B. Martin ◽  
L. W. Burggraf
Keyword(s):  
Signal To Noise Ratio ◽  
Reconstruction Algorithm ◽  
Filtered Backprojection ◽  
Line Broadening ◽  
Compton Scatter ◽  
X Ray ◽  
Tomography System ◽  
Transmission Computed Tomography ◽  
High Purity Germanium ◽  
Scattered Energy

ABSTRACTThe viability of a Compton scattering tomography system for nondestructively inspecting thin, low Z samples for corrosion is examined. This technique differs from conventional x-ray backscatter NDI because it does not rely on narrow collimation of source and detectors to examine small volumes in the sample. Instead, photons of a single energy are backscattered from the sample and their scattered energy spectra are measured at multiple detector locations, and these spectra are then used to reconstruct an image of the object. This multiplexed Compton scatter tomography technique interrogates multiple volume elements simultaneously. Thin samples less than 1 cm thick and made of low Z materials are best imaged with gamma rays at or below 100 keV energy. At this energy, Compton line broadening becomes an important resolution limitation. An analytical model has been developed to simulate the signals collected in a demonstration system consisting of an array of planar high-purity germanium detectors. A technique for deconvolving the effects of Compton broadening and detector energy resolution from signals with additive noise is also presented. A filtered backprojection image reconstruction algorithm with similarities to that used in conventional transmission computed tomography is developed. A simulation of a 360–degree inspection gives distortion-free results. In a simulation of a single-sided inspection, a 5 mm × 5 mm corrosion flaw with 50% density is readily identified in 1-cm thick aluminum phantom when the signal to noise ratio in the data exceeds 28.

Solvent-Ligand Interactions in Colloidal Nanocrystals

2018 ◽  
Author(s):  
Jonathan De Roo ◽  
Nuri Yazdani ◽  
Emile Drijvers ◽  
Alessandro Lauria ◽  
Jorick Maes ◽  
...  
Keyword(s):  
Direct Method ◽  
Line Broadening ◽  
H Nmr ◽  
Size Dependent ◽  
Line Shape Analysis ◽  
Wide Range ◽  
Nanocrystal Synthesis ◽  
Ligand Interactions ◽  
Indispensable Tool ◽  
Theoretical Evidence

<p>Although solvent-ligand interactions play a major role in nanocrystal synthesis, dispersion formulation and assembly, there is currently no direct method to study this. Here we examine the broadening of <sup>1</sup>H NMR resonances associated with bound ligands, and turn this poorly understood descriptor into a tool to assess solvent-ligand interactions. We show that the line broadening has both a homogeneous and a heterogeneous component. The former is nanocrystal-size dependent and the latter results from solvent-ligand interactions. Our model is supported by experimental and theoretical evidence that correlates broad NMR lines with poor ligand solvation. This correlation is found across a wide range of solvents, extending from water to hexane, for both hydrophobic and hydrophilic ligand types, and for a multitude of oxide, sulfide and selenide nanocrystals. Our findings thus put forward NMR line shape analysis as an indispensable tool to form, investigate and manipulate nanocolloids.</p>

Line widths, sensitivity and artifacts in33S NMR Spectra: The case of aqueous sulphides

1986 ◽  
Vol 24 (11) ◽  
pp. 1004-1007 ◽  
Author(s):  
P. S. Belton ◽  
I. J. Cox ◽  
R. K. Harris
Keyword(s):  
Nmr Spectra ◽  
Line Widths
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