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Journal of Magnetic Resonance, Series A最新文献

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Translating Conduction-Electron Spin-Resonance Lines into Lorentzian Lines 电导-电子自旋共振线转化为洛伦兹线
Journal of Magnetic Resonance, Series A Pub Date : 1996-10-01 DOI: 10.1006/jmra.1996.0196
L. Walmsley
{"title":"Translating Conduction-Electron Spin-Resonance Lines into Lorentzian Lines","authors":"L. Walmsley","doi":"10.1006/jmra.1996.0196","DOIUrl":"10.1006/jmra.1996.0196","url":null,"abstract":"<div><p>The Dysonian line in the limit<em>d</em>&lt; or ∼ δ, where<em>d</em>is the thickness and δ the skin depth, was fitted to a combination of absorption and dispersion Lorentzian lines. This procedure allows one to determine not only microwave conductivity from the Dysonian line but also the true<em>g</em>value, linewidth, and paramagnetic susceptibility by the measurement of five parameters of the ESR absorption-derivative Dysonian line.</p></div>","PeriodicalId":16165,"journal":{"name":"Journal of Magnetic Resonance, Series A","volume":"122 2","pages":"Pages 209-213"},"PeriodicalIF":0.0,"publicationDate":"1996-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmra.1996.0196","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81536345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 14
Sensitivity and Lineshape Improvements of MQ-MAS by Rotor-Synchronized Data Acquisition 转子同步数据采集对MQ-MAS灵敏度和线形的改进
Journal of Magnetic Resonance, Series A Pub Date : 1996-10-01 DOI: 10.1006/jmra.1996.0202
Dominique Massiot
{"title":"Sensitivity and Lineshape Improvements of MQ-MAS by Rotor-Synchronized Data Acquisition","authors":"Dominique Massiot","doi":"10.1006/jmra.1996.0202","DOIUrl":"10.1006/jmra.1996.0202","url":null,"abstract":"","PeriodicalId":16165,"journal":{"name":"Journal of Magnetic Resonance, Series A","volume":"122 2","pages":"Pages 240-244"},"PeriodicalIF":0.0,"publicationDate":"1996-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmra.1996.0202","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84017440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 135
A Quaternion Analysis of Time Symmetry in Spin-1 Excitation 自旋-1激励中时间对称性的四元数分析
Journal of Magnetic Resonance, Series A Pub Date : 1996-10-01 DOI: 10.1006/jmra.1996.0194
Dalian Lu, Shahida Ali , David J Siminovitch
{"title":"A Quaternion Analysis of Time Symmetry in Spin-1 Excitation","authors":"Dalian Lu,&nbsp;Shahida Ali ,&nbsp;David J Siminovitch","doi":"10.1006/jmra.1996.0194","DOIUrl":"10.1006/jmra.1996.0194","url":null,"abstract":"<div><p>The role of time symmetry in composite-pulse design is examined by considering a phase-alternating composite pulse pair {π(<em>I</em>= <span><math><mtext>1</mtext><mtext>2</mtext></math></span>), π/2(<em>I</em>= 1)}, where the spin-1 excitation pulse has been derived from its spin-<span><math><mtext>1</mtext><mtext>2</mtext></math></span> progenitor by halving the pulse durations. The quaternion calculus is used to define the quaternion elements (Euler–Rodrigues parameters) of each composite pulse. In this manner, it is shown how an Euler–Rodrigues (ER) parametrization of the consecutive rotations implicit in each composite pulse can be used to derive simple phase and amplitude relationships between the members of such a {π(<em>I</em>= <span><math><mtext>1</mtext><mtext>2</mtext></math></span>), π/2(<em>I</em>= 1)} pulse pair. The simplicity and compactness of the ER parametrization is then used to identify optimal time-symmetric sequences for spin-1 excitation by using the Lagrange multiplier method.</p></div>","PeriodicalId":16165,"journal":{"name":"Journal of Magnetic Resonance, Series A","volume":"122 2","pages":"Pages 192-203"},"PeriodicalIF":0.0,"publicationDate":"1996-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmra.1996.0194","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88124377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
The Memory-Function Technique for the Calculation of Pulsed-Gradient NMR Signals in Confined Geometries 受限几何中脉冲梯度核磁共振信号计算的记忆函数技术
Journal of Magnetic Resonance, Series A Pub Date : 1996-10-01 DOI: 10.1006/jmra.1996.0188
Daniel Sheltraw, V.M. Kenkre
{"title":"The Memory-Function Technique for the Calculation of Pulsed-Gradient NMR Signals in Confined Geometries","authors":"Daniel Sheltraw,&nbsp;V.M. Kenkre","doi":"10.1006/jmra.1996.0188","DOIUrl":"10.1006/jmra.1996.0188","url":null,"abstract":"<div><p>An approximation technique for the calculation of pulsed-gradient NMR signals in confined spaces is introduced on the basis of a memory-function formalism and compared to the well-known cumulant expansion technique. The validity of the technique is investigated for the cases of a time-independent field gradient and a gradient consisting of two pulses of finite duration. It is found that the validity is governed by the ratio of two characteristic times: the time for the spins to traverse the dimensions of the confining space through diffusion and the reciprocal of the extreme difference between values of the precession frequency of the spin. Oscillations in the time evolution of the signal for the constant gradient, as well as oscillations in the (gradient) field dependence for the two-pulse gradient, which are both characteristic of the exact signals, are predicted by the new technique but not by the cumulant technique. The cumulant results are shown to arise as an approximate consequence of the memory results.</p></div>","PeriodicalId":16165,"journal":{"name":"Journal of Magnetic Resonance, Series A","volume":"122 2","pages":"Pages 126-136"},"PeriodicalIF":0.0,"publicationDate":"1996-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmra.1996.0188","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79863078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 19
Sensitive Measurement and Unambiguous Assignment of Long-Range13C,13C Coupling Constants at Natural Isotope Abundance 天然同位素丰度中13C、13C耦合常数的灵敏测量和明确赋值
Journal of Magnetic Resonance, Series A Pub Date : 1996-10-01 DOI: 10.1006/jmra.1996.0203
Wiktor Koźmiński , Daniel Nanz
{"title":"Sensitive Measurement and Unambiguous Assignment of Long-Range13C,13C Coupling Constants at Natural Isotope Abundance","authors":"Wiktor Koźmiński ,&nbsp;Daniel Nanz","doi":"10.1006/jmra.1996.0203","DOIUrl":"10.1006/jmra.1996.0203","url":null,"abstract":"","PeriodicalId":16165,"journal":{"name":"Journal of Magnetic Resonance, Series A","volume":"122 2","pages":"Pages 245-247"},"PeriodicalIF":0.0,"publicationDate":"1996-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmra.1996.0203","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86919701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 15
1H NMRD Profile and ESR Lineshape Calculation for an Isotropic Electron Spin System withS= 7/2. A Generalized Modified Solomon–Bloembergen–Morgan Theory for Nonextreme-Narrowing Conditions s = 7/2的各向同性电子自旋体系的1H NMRD剖面和ESR线形计算非极值变窄条件下的广义修正Solomon-Bloembergen-Morgan理论
Journal of Magnetic Resonance, Series A Pub Date : 1996-10-01 DOI: 10.1006/jmra.1996.0193
Erik Strandberg, Per-Olof Westlund
{"title":"1H NMRD Profile and ESR Lineshape Calculation for an Isotropic Electron Spin System withS= 7/2. A Generalized Modified Solomon–Bloembergen–Morgan Theory for Nonextreme-Narrowing Conditions","authors":"Erik Strandberg,&nbsp;Per-Olof Westlund","doi":"10.1006/jmra.1996.0193","DOIUrl":"10.1006/jmra.1996.0193","url":null,"abstract":"<div><p>A generalization of the modified Solomon–Bloembergen–Morgan (MSBM) theory is presented for electron-spin quantum number<em>S</em>= 7/2 taking multiexponential electron-spin relaxation into account. The theoretical approach closely follows P.-O. Westlund [<em>Mol. Phys.</em>85, 1165–1178 (1995)]. In the nonextreme-narrowing regime for the electron spin system, three correction terms to the traditional MSBM equations arise. They are all derived in closed analytical form to give the generalized equations in a simple and convenient form: MSBM × (1 + correction). The ESR lineshape function for<em>S</em>= 7/2 is also given in closed analytical form. A number of proton<em>T</em><sub>1</sub>NMRD profiles representing different Gd(III) complexes are investigated, using a spectral density function of the transient ZFS interaction which allows for two relaxation times. For Gd–macromolecular complexes the largest deviation from the traditional MSBM theory may be about 15.2%, but for the parameter sets investigated the corrections were about 2–3%. A computer program is developed which calculates the NMRD profile and the ESR lineshape (X band or Q band) for the set of model parameters. These parameters describe the electron spin system in terms of Δ<sub>t</sub>(the root-mean-square value of the transient ZFS interaction) and τ<sub>v1</sub>, τ<sub>v2</sub>, and<em>S</em><sub>0</sub>(correlation times and an order parameter of the transient ZFS correlation function). For the paramagnetically enhanced nuclear (<em>I</em>= <span><math><mtext>1</mtext><mtext>2</mtext></math></span>) spin relaxation, the parameters τ<sub>R</sub>(the reorientational correlation time),<em>q</em>(the number of fast exchanging water molecules in the first hydration shell), and<em>r</em><sub>IS</sub>(the point spin–dipole distance) are also used.</p></div>","PeriodicalId":16165,"journal":{"name":"Journal of Magnetic Resonance, Series A","volume":"122 2","pages":"Pages 179-191"},"PeriodicalIF":0.0,"publicationDate":"1996-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmra.1996.0193","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89662027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 46
Extension of CEDRA to Homonuclear Coherence Transfers 将CEDRA扩展到同核相干转移
Journal of Magnetic Resonance, Series A Pub Date : 1996-10-01 DOI: 10.1006/jmra.1996.0205
Christopher A. Klug , Jacob Schaefer
{"title":"Extension of CEDRA to Homonuclear Coherence Transfers","authors":"Christopher A. Klug ,&nbsp;Jacob Schaefer","doi":"10.1006/jmra.1996.0205","DOIUrl":"10.1006/jmra.1996.0205","url":null,"abstract":"","PeriodicalId":16165,"journal":{"name":"Journal of Magnetic Resonance, Series A","volume":"122 2","pages":"Pages 251-253"},"PeriodicalIF":0.0,"publicationDate":"1996-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmra.1996.0205","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79152415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
Solid-State NMR of 1-Propyltetrazole Complexes of Iron(II) and Zinc(II). 1.1H Spin–Lattice Relaxation Time 铁(II)和锌(II)的1-丙基四唑配合物的固体核磁共振。1.1H自旋-晶格弛豫时间
Journal of Magnetic Resonance, Series A Pub Date : 1996-10-01 DOI: 10.1006/jmra.1996.0191
Mónika Bokor , Tamás Marek , Kálmán Tompa
{"title":"Solid-State NMR of 1-Propyltetrazole Complexes of Iron(II) and Zinc(II). 1.1H Spin–Lattice Relaxation Time","authors":"Mónika Bokor ,&nbsp;Tamás Marek ,&nbsp;Kálmán Tompa","doi":"10.1006/jmra.1996.0191","DOIUrl":"10.1006/jmra.1996.0191","url":null,"abstract":"<div><p>Proton spin–lattice relaxation times were measured between 2.2 K and room temperature in [Zn(ptz)<sub>6</sub>](BF<sub>4</sub>)<sub>2</sub>(ptz = 1-<em>n</em>-propyl-1<em>H</em>-tetrazole) and in the spin-crossover complex [Fe(ptz)<sub>6</sub>](BF<sub>4</sub>)<sub>2</sub>. Three different types of intramolecular motion of the propyl group are suggested in [Zn(ptz)<sub>6</sub>](BF<sub>4</sub>)<sub>2</sub>, namely tunneling and classical rotation of methyl groups and rotation of methylene groups. Correlation times and activation energies are calculated for tunneling rotation of the CH<sub>3</sub>group and for the classical (hindered) rotations of –CH<sub>3</sub>and –CH<sub>2</sub>–CH<sub>3</sub>as reorientations over a three-well asymmetrical potential. In [Fe(ptz)<sub>6</sub>](BF<sub>4</sub>)<sub>2</sub>the mechanism for the paramagnetic relaxation is found to be of the rapid-diffusion type according to the theory of Lowe and Tse, and the intramolecular motions are suggested to be the same as for the zinc complex.</p></div>","PeriodicalId":16165,"journal":{"name":"Journal of Magnetic Resonance, Series A","volume":"122 2","pages":"Pages 157-164"},"PeriodicalIF":0.0,"publicationDate":"1996-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmra.1996.0191","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82491077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 9
Simple Improvements in Spinning-Speed Control for MAS NMR Experiments MAS核磁共振实验转速控制的简单改进
Journal of Magnetic Resonance, Series A Pub Date : 1996-10-01 DOI: 10.1006/jmra.1996.0201
Lamy Chopin, Richard Rosanske, Terry Gullion
{"title":"Simple Improvements in Spinning-Speed Control for MAS NMR Experiments","authors":"Lamy Chopin,&nbsp;Richard Rosanske,&nbsp;Terry Gullion","doi":"10.1006/jmra.1996.0201","DOIUrl":"10.1006/jmra.1996.0201","url":null,"abstract":"","PeriodicalId":16165,"journal":{"name":"Journal of Magnetic Resonance, Series A","volume":"122 2","pages":"Pages 237-239"},"PeriodicalIF":0.0,"publicationDate":"1996-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmra.1996.0201","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77890254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 10
Author Index for Volume 122 第122卷作者索引
Journal of Magnetic Resonance, Series A Pub Date : 1996-10-01 DOI: 10.1006/jmra.1996.0206
{"title":"Author Index for Volume 122","authors":"","doi":"10.1006/jmra.1996.0206","DOIUrl":"https://doi.org/10.1006/jmra.1996.0206","url":null,"abstract":"","PeriodicalId":16165,"journal":{"name":"Journal of Magnetic Resonance, Series A","volume":"122 2","pages":"Page 254"},"PeriodicalIF":0.0,"publicationDate":"1996-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/jmra.1996.0206","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137062807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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