1
|
Theoretical approaches to control spin dynamics in solid-state nuclear magnetic resonance. J CHEM SCI 2015. [DOI: 10.1007/s12039-015-0977-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
2
|
Mananga ES. Applications of Floquet-Magnus expansion, average Hamiltonian theory and Fer expansion to study interactions in solid state NMR when irradiated with the magic-echo sequence. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2013; 55-56:54-62. [PMID: 24034855 PMCID: PMC5378413 DOI: 10.1016/j.ssnmr.2013.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Revised: 06/21/2013] [Accepted: 08/13/2013] [Indexed: 06/02/2023]
Abstract
This work presents the possibility of applying the Floquet-Magnus expansion and the Fer expansion approaches to the most useful interactions known in solid-state nuclear magnetic resonance using the magic-echo scheme. The results of the effective Hamiltonians of these theories and average Hamiltonian theory are presented.
Collapse
Affiliation(s)
- Eugene Stephane Mananga
- Harvard Medical School and Massachusetts General Hospital, Center for Advanced Medical Imaging Sciences, Division of Nuclear Medicine and Molecular Imaging Physics, Department of Radiology, 55 Fruit Street, Boston, MA 02114, United States.
| |
Collapse
|
3
|
Stephane Mananga E. Criteria to average out the chemical shift anisotropy in solid-state NMR when irradiated with BABA I, BABA II, and C7 radiofrequency pulse sequences. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2013; 55-56:63-72. [PMID: 24060139 DOI: 10.1016/j.ssnmr.2013.08.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 08/20/2013] [Accepted: 08/26/2013] [Indexed: 06/02/2023]
Abstract
Floquet-Magnus expansion is used to study the effect of chemical shift anisotropy in solid-state NMR of rotating solids. The chemical shift interaction is irradiated with two types of radiofrequency pulse sequences: BABA and C7. The criteria for the chemical shift anisotropy to be averaged out in each rotor period are obtained.
Collapse
Affiliation(s)
- Eugene Stephane Mananga
- Harvard University, Harvard Medical School, and Massachusetts General Hospital, Center for Advanced Medical Imaging Sciences, Division of Nuclear Medicine and Molecular Imaging Physics, Department of Radiology, 55 Fruit Street, Boston, MA 02114, USA.
| |
Collapse
|
4
|
Mananga ES. Progress in spin dynamics solid-state nuclear magnetic resonance with the application of Floquet-Magnus expansion to chemical shift anisotropy. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2013; 54:1-7. [PMID: 23711337 PMCID: PMC3759595 DOI: 10.1016/j.ssnmr.2013.04.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Revised: 04/09/2013] [Accepted: 04/22/2013] [Indexed: 06/02/2023]
Abstract
The purpose of this article is to present an historical overview of theoretical approaches used for describing spin dynamics under static or rotating experiments in solid state nuclear magnetic resonance. The article gives a brief historical overview for major theories in nuclear magnetic resonance and the promising theories. We present the first application of Floquet-Magnus expansion to chemical shift anisotropy when irradiated by BABA pulse sequence.
Collapse
Affiliation(s)
- Eugene Stephane Mananga
- Harvard University, Harvard Medical School, and Massachusetts General Hospital, Center for Advanced Radiological Sciences, Division of Nuclear Medicine and Molecular Imaging Physics, Department of Radiology, 55 Fruit Street, Boston, MA 02114, USA.
| |
Collapse
|
5
|
Mananga ES, Reid AE. Investigation of the Effect of Finite Pulse Errors on BABA Pulse Sequence Using Floquet-Magnus Expansion Approach. Mol Phys 2013; 111:243-257. [PMID: 25792763 PMCID: PMC4362536 DOI: 10.1080/00268976.2012.718379] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This paper presents the study of finite pulse widths for the BABA pulse sequence using the Floquet-Magnus expansion (FME) approach. In the FME scheme, the first order F1 is identical to its counterparts in average Hamiltonian theory (AHT) and Floquet theory (FT). However, the timing part in the FME approach is introduced via the Λ1 (t) function not present in other schemes. This function provides an easy way for evaluating the spin evolution during "the time in between" through the Magnus expansion of the operator connected to the timing part of the evolution. The evaluation of Λ1 (t) is useful especially for the analysis of the non-stroboscopic evolution. Here, the importance of the boundary conditions, which provides a natural choice of Λ1 (0) is ignored. This work uses the Λ1 (t) function to compare the efficiency of the BABA pulse sequence with δ - pulses and the BABA pulse sequence with finite pulses. Calculations of Λ1 (t) and F1 are presented.
Collapse
Affiliation(s)
- Eugene S. Mananga
- HARVARD UNIVERSITY, HARVARD MEDICAL SCHOOL AND MASSACHUSETTS GENERAL HOSPITAL Center for Advanced Radiological Sciences, Division of Nuclear Medicine and Molecular Imaging Physics Department of Radiology, 55 Fruit Street, Boston, Massachusetts, 02114
| | - Alicia E. Reid
- THE CITY UNIVERSITY OF NEW YORK, MEDGAR EVERS COLLEGE, 1638 Bedford Avenue, Brooklyn, NY, 11225
| |
Collapse
|
6
|
Mananga ES, Reid AE, Charpentier T. Efficient theory of dipolar recoupling in solid-state nuclear magnetic resonance of rotating solids using Floquet-Magnus expansion: application on BABA and C7 radiofrequency pulse sequences. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2012; 41:32-47. [PMID: 22197191 PMCID: PMC4362537 DOI: 10.1016/j.ssnmr.2011.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 09/20/2011] [Accepted: 11/11/2011] [Indexed: 05/31/2023]
Abstract
This article describes the use of an alternative expansion scheme called Floquet-Magnus expansion (FME) to study the dynamics of spin system in solid-state NMR. The main tool used to describe the effect of time-dependent interactions in NMR is the average Hamiltonian theory (AHT). However, some NMR experiments, such as sample rotation and pulse crafting, seem to be more conveniently described using the Floquet theory (FT). Here, we present the first report highlighting the basics of the Floquet-Magnus expansion (FME) scheme and hint at its application on recoupling sequences that excite more efficiently double-quantum coherences, namely BABA and C7 radiofrequency pulse sequences. The use of Λ(n)(t) functions available only in the FME scheme, allows the comparison of the efficiency of BABA and C7 sequences.
Collapse
Affiliation(s)
- Eugene S Mananga
- Commissariat A L' Energie Atomique, Neurospin/I2BM, Laboratoire de Resonance Magnetique Nucleaire, CEA-Saclay, Bât 145, Point Courrier 156F-91191 Gif-sur-Yvette cedex, France.
| | | | | |
Collapse
|
7
|
Abstract
Dipolar recoupling techniques in solid-state nuclear magnetic resonance (NMR) consist of radio frequency (rf) pulse sequences applied in synchrony with magic-angle spinning (MAS) that create nonzero average magnetic dipole-dipole couplings under MAS. Stochastic dipolar recoupling (SDR) is a variant in which randomly chosen rf carrier frequency offsets are introduced to cause random phase modulations of individual pairwise couplings in the dipolar spin Hamiltonian. Several aspects of SDR are investigated through analytical theory and numerical simulations: (1) An analytical expression for the evolution of nuclear spin polarization under SDR in a two-spin system is derived and verified through simulations, which show a continuous evolution from coherent, oscillatory polarization exchange to incoherent, exponential approach to equilibrium as the range of random carrier offsets (controlled by a parameter f(max)) increases; (2) in a many-spin system, polarization transfers under SDR are shown to be described accurately by a rate matrix in the limit of large f(max), with pairwise transfer rates that are proportional to the inverse sixth power of pairwise internuclear distances; (3) quantum mechanical interferences among noncommuting pairwise dipole-dipole couplings, which are a complicating factor in solid-state NMR studies of molecular structures by traditional dipolar recoupling methods, are shown to be absent from SDR data in the limit of large f(max), provided that coupled nuclei have distinct NMR chemical shifts.
Collapse
Affiliation(s)
- Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA.
| |
Collapse
|
8
|
|
9
|
Tycko R. Introduction to special topic: new developments in magnetic resonance. J Chem Phys 2008; 128:052101. [PMID: 18266405 DOI: 10.1063/1.2833958] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA.
| |
Collapse
|
10
|
Abstract
Constant-time dipolar recoupling pulse sequences are advantageous in structural studies by solid state nuclear magnetic resonance (NMR) with magic-angle spinning (MAS) because they yield experimental data that are relatively insensitive to radio-frequency pulse imperfections and nuclear spin relaxation processes. A new approach to the construction of constant-time homonuclear dipolar recoupling sequences is described, based on symmetry properties of the recoupled dipole-dipole interaction Hamiltonian under cyclic displacements in time with respect to the MAS sample rotation period. A specific symmetry-based pulse sequence called PITHIRDS-CT is introduced and demonstrated experimentally. (13)C NMR data for singly-(13)C-labeled amino acid powders and amyloid fibrils indicate the effectiveness of PITHIRDS-CT in measurements of intermolecular distances in solids. (15)N-detected and (13)C-detected measurements of intramolecular (15)N-(15)N distances in peptides with alpha-helical and beta-sheet structures indicate the utility of PITHIRDS-CT in studies of molecular conformations, especially measurements of backbone psi torsion angles in peptides containing uniformly (15)N- and (13)C-labeled amino acids.
Collapse
Affiliation(s)
- Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA.
| |
Collapse
|
11
|
Nishiyama Y, Yamazaki T. Zero-field nuclear magnetic resonance in high field by modulated rf sequences. J Chem Phys 2007; 126:134501. [PMID: 17430041 DOI: 10.1063/1.2713386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The authors propose a novel approach to design and evaluate sequences for zero-field NMR spectra in high field (ZFHF) by using amplitude and phase modulated rf sequences. ZFHF provide sharp peaks for the dipolar interaction between two nuclear spins even if the orientation of the molecules is distributed. The internuclear distance r can be directly obtained from the peak position which is proportional to r-3. Numerous ZFHF sequences are obtained. A sequence is selected from them by the systematic evaluation of the sequences. The new ZFHF sequence is less affected by chemical shift anisotropy (CSA) than the previous sequences; the sequence can be used for systems with large CSA such as a dipolar coupled 13C-pair system under realistically high field. 13C ZFHF spectra of 13C2 diammonium succinate and 13C2 diammonium oxalate were observed under the 9.4 T field.
Collapse
Affiliation(s)
- Yusuke Nishiyama
- Genomic Sciences Center, RIKEN Institute, Yokohama, Kanagawa 230-0045, Japan.
| | | |
Collapse
|
12
|
Cho H. 2-D homonuclear correlation and separated local field experiments for solids with strong homonuclear dipolar couplings. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2006; 29:219-26. [PMID: 16325381 DOI: 10.1016/j.ssnmr.2005.10.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Revised: 09/24/2005] [Indexed: 05/05/2023]
Abstract
An experiment for acquiring two-dimensional homonuclear correlation spectra of nuclei in solids in the presence of strong homonuclear dipolar couplings is described. The experiment utilizes a multiple-pulse homonuclear decoupling sequence with an effective precession axis parallel to the rotating frame z-axis during the evolution and detection periods. A multiple-pulse sequence that suppresses chemical shift and heteronuclear dipolar coupling evolution and scales the static homonuclear dipolar coupling is proposed for the mixing period. The evolution during the mixing period is analogous to the dynamics of the mixing period in solution-state TOCSY experiments, and can be interpreted as the oscillatory exchange of longitudinal magnetization between coupled spins. For nuclides with large gyromagnetic ratios, the static homonuclear dipolar interaction will be substantially larger than the mechanisms used to develop internuclear correlations in solution state 2-D experiments, which should make it possible to establish correlations over much longer distances and with significantly shorter mixing times. Extensions to separated local field experiments are discussed.
Collapse
Affiliation(s)
- Herman Cho
- Environmental Molecular Sciences Laboratory MS K8-98, Pacific Northwest National Laboratory, P. O. Box 999, Richland, Washington 99352, USA.
| |
Collapse
|
13
|
Havlin RH, Walls JD, Pines A. Isotropic proton-detected local-field nuclear magnetic resonance in solids. J Chem Phys 2005; 122:074507. [PMID: 15743254 DOI: 10.1063/1.1844296] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A nuclear magnetic resonance method is presented which produces linear, isotropic proton-detected local-field spectra for INS spin systems in powdered samples. The method, heteronuclear isotropic evolution (HETIE), refocuses the anisotropic portion of the heteronuclear dipolar coupling frequencies by evolving the system under a series of specially designed Hamiltonians and evolution pathways. The theory behind HETIE is presented along with experimental studies conducted on a powdered sample of ferrocene, demonstrating the methodology outlined in this paper. Applications of HETIE for use in structure determination in the solid state are discussed.
Collapse
Affiliation(s)
- Robert H Havlin
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | |
Collapse
|
14
|
Brinkmann A, Edén M. Second order average Hamiltonian theory of symmetry-based pulse schemes in the nuclear magnetic resonance of rotating solids: Application to triple-quantum dipolar recoupling. J Chem Phys 2004; 120:11726-45. [PMID: 15268208 DOI: 10.1063/1.1738102] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The average Hamiltonian theory (AHT) of several classes of symmetry-based radio-frequency pulse sequences is developed to second order, allowing quantitative analyses of a wide range of recoupling and decoupling applications in magic-angle-spinning solid state nuclear magnetic resonance. General closed analytical expressions are presented for a cross term between any two interactions recoupled to second order AHT. We classify them into different categories and show that some properties of the recoupling pulse sequence may be predicted directly from this classification. These results are applied to examine a novel homonuclear recoupling strategy, effecting a second order average dipolar Hamiltonian comprising trilinear triple quantum (3Q) spin operators. We discuss general features and design principles of such 3Q recoupling sequences and demonstrate by numerical simulations and experiments that they provide more efficient excitation of (13)C 3Q coherences compared to previous techniques. We passed up to 15% of the signal through a state of 3Q coherence in rotating powders of uniformly (13)C-labeled alanine and tyrosine. Second order recoupling-based (13)C homonuclear 3Q correlation spectroscopy is introduced and demonstrated on tyrosine.
Collapse
Affiliation(s)
- Andreas Brinkmann
- Physical Chemistry/Solid State NMR, NSRIM Center, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
| | | |
Collapse
|
15
|
Carravetta M, Johannessen OG, Levitt MH. Beyond the T1 limit: singlet nuclear spin states in low magnetic fields. PHYSICAL REVIEW LETTERS 2004; 92:153003. [PMID: 15169282 DOI: 10.1103/physrevlett.92.153003] [Citation(s) in RCA: 268] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2003] [Indexed: 05/24/2023]
Abstract
Low-field nuclear spin singlet states may be used to store nuclear spin order in a room temperature liquid for a time much longer than the spin-lattice relaxation time constant T1. The low-field nuclear spin singlets are unaffected by intramolecular dipole-dipole relaxation, which is generally the predominant relaxation mechanism. We demonstrate storage of nuclear spin order for more than 10 times longer than the measured value of T1. This phenomenon may facilitate the development of nuclear spin hyperpolarization methods and may allow the study of motional processes which occur too slowly for existing NMR techniques. This is the first time that the memory of nuclear spins has been extended well beyond the T1 limit in a system lacking intrinsic magnetic equivalence.
Collapse
Affiliation(s)
- Marina Carravetta
- School of Chemistry, University of Southampton, SO17 1BJ, United Kingdom
| | | | | |
Collapse
|
16
|
Walls JD, Blanton WB, Havlin RH, Pines A. Creating isotropic dipolar spectra for a pair of dipole coupled spins in high-field. Chem Phys Lett 2002. [DOI: 10.1016/s0009-2614(02)01188-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
17
|
Tycko R. Biomolecular solid state NMR: advances in structural methodology and applications to peptide and protein fibrils. Annu Rev Phys Chem 2001; 52:575-606. [PMID: 11326075 DOI: 10.1146/annurev.physchem.52.1.575] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Solid state nuclear magnetic resonance (NMR) methods can provide atomic-level structural constraints on peptides and proteins in forms that are not amenable to characterization by other high-resolution structural techniques, owing to insolubility, high molecular weight, noncrystallinity, or other characteristics. Important examples include peptide and protein fibrils and membrane-bound peptides and proteins. Recent advances in solid state NMR methodology aimed at structural problems in biological systems are reviewed. The power of these methods is illustrated by experimental results on amyloid fibrils and other protein fibrils.
Collapse
Affiliation(s)
- R Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA.
| |
Collapse
|
18
|
Michal CA, Tycko R. Time-reversal of the evolution of a dipole-coupled, many-spin system under continuous resonant irradiation. J Chem Phys 2001. [DOI: 10.1063/1.1330239] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
19
|
Cho H. Off-resonance multiple-pulse dynamics in solid-state NMR spectroscopy: A revised coherent averaging theory analysis. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 1999; 141:164-179. [PMID: 10527754 DOI: 10.1006/jmre.1999.1859] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The standard coherent averaging theory treatment of the resonance offset interaction is compared to exact calculations for multiple-pulse solid-state NMR experiments. Significant differences between coherent averaging approximations and exact results are revealed, even for idealized conditions. A revision of the standard analysis is proposed as a way of improving the description of the off-resonance dynamics in these experiments. We use the insights obtained from this investigation to derive a qualitatively new type of homonuclear decoupling sequence, and evaluate the performance and advantages of this sequence with both simulations and experimental tests. Copyright 1999 Academic Press.
Collapse
Affiliation(s)
- H Cho
- Environmental Molecular Sciences Laboratory MS K8-98, Pacific Northwest National Laboratory, Richland, Washington, 99352, USA
| |
Collapse
|
20
|
Hodgkinson P, Emsley L. The accuracy of distance measurements in solid-state NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 1999; 139:46-59. [PMID: 10388583 DOI: 10.1006/jmre.1999.1759] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The accuracy with which distances can be measured using dipolar recoupling experiments in solid-state NMR is investigated. The relative precision of experiments in a three spin system versus an isolated spin pair is found to depend very strongly on the nature of the coupling Hamiltonian. The accuracy of distances measured in even the simplified three spin system is seen to be very poor for existing homonuclear recoupling Hamiltonians. This suggests that it would be difficult to exploit broadband homonuclear recoupling to measure geometrical information reliably in complex spin systems. These conclusions apply equally to both single-crystal studies and powder samples. In contrast, the presence of additional spins has marginal impact on the accuracy when the coupling Hamiltonians commute with each other, as in the case of heteronuclear recoupling. The possibility of creating such a Hamiltonian for homonuclear recoupling using a suitable rotor-synchronized pulse sequence is discussed.
Collapse
Affiliation(s)
- P Hodgkinson
- CNRS/ENS-Lyon, Ecole Normale Supérieure de Lyon, 46 allée d'Italie, Lyon, 69364, France
| | | |
Collapse
|
21
|
Tycko R, Weliky DP, Berger AE. Investigation of molecular structure in solids by two‐dimensional NMR exchange spectroscopy with magic angle spinning. J Chem Phys 1996. [DOI: 10.1063/1.472708] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
22
|
Ernst M, Kolbert AC, Schmidt‐Rohr K, Pines A. Isotropic second‐order dipolar shifts in the rotating frame. J Chem Phys 1996. [DOI: 10.1063/1.471579] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
23
|
Llor A, Olejniczak Z, Pines A. Coherent isotropic averaging in zero‐field nuclear magnetic resonance. I. General theory and icosahedral sequences. J Chem Phys 1995. [DOI: 10.1063/1.469584] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
24
|
|
25
|
Tycko R, Smith SO. Symmetry principles in the design of pulse sequences for structural measurements in magic angle spinning nuclear magnetic resonance. J Chem Phys 1993. [DOI: 10.1063/1.465078] [Citation(s) in RCA: 120] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
26
|
Zero-Field Spin Dynamics and Relaxation. ACTA ACUST UNITED AC 1992. [DOI: 10.1016/b978-0-12-025517-7.50006-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
27
|
Llor A, Olejniczak Z, Sachleben J, Pines A. Scaling and time reversal of spin couplings in zero-field NMR. PHYSICAL REVIEW LETTERS 1991; 67:1989-1992. [PMID: 10044307 DOI: 10.1103/physrevlett.67.1989] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
28
|
|
29
|
Tycko R, Dabbagh G. Measurement of nuclear magnetic dipole—dipole couplings in magic angle spinning NMR. Chem Phys Lett 1990. [DOI: 10.1016/0009-2614(90)87235-j] [Citation(s) in RCA: 201] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
30
|
|
31
|
|