نتایج جستجو برای: quadrupolar nuclei

تعداد نتایج: 62901  

2005
Jonathan R. Gair Daniel J. Kennefick Shane L. Larson

1550-7998=20 The capture of compact bodies by black holes in galactic nuclei is an important prospective source for low frequency gravitational wave detectors, such as the planned Laser Interferometer Space Antenna. This paper calculates, using a semirelativistic approximation, the total energy and angular momentum lost to gravitational radiation by compact bodies on very high eccentricity orbi...

2005
M. Maćkowiak

Two-dimensional exchange Cl nuclear quadrupole resonance spectroscopy for studies of the CCl3-group reorientation processes in hexachloroethane and chloral hydrate has been applied. Experimental results were interpreted on the basis of the 2D exchange nuclear quadrupole resonance theory, which takes into account the off-resonance irradiation. It has been demonstrated that 2D nuclear quadrupole ...

Journal: :The Journal of chemical physics 2017
Andrey Yachmenev Jochen Küpper

A general algorithm for computing the quadrupole-hyperfine effects in the rovibrational spectra of polyatomic molecules is presented for the case of ammonia (NH3). The method extends the general variational approach TROVE [J. Mol. Spectrosc. 245, 126-140 (2007)] by adding the extra term in the Hamiltonian that describes the nuclear quadrupole coupling, with no inherent limitation on the number ...

Journal: :Journal of magnetic resonance 2008
R Auccaise J Teles R S Sarthour T J Bonagamba I S Oliveira E R deAzevedo

This article reports a relaxation study in an oriented system containing spin 3/2 nuclei using quantum state tomography (QST). The use of QST allowed evaluating the time evolution of all density matrix elements starting from several initial states. Using an appropriated treatment based on the Redfield theory, the relaxation rate of each density matrix element was measured and the reduced spectr...

2002
Zhehong Gan Philip Grandinetti

The theory of rotary resonance in multiple-quantum magic-angle spinning (MQMAS) experiment is presented. The rotary resonance effect can enhance the efficiency of MQMAS experiment for high-resolution NMR spectra of half-integer quadrupolar nuclei [J. Chem. Phys. 114 (2001) 4618]. Using a spin-1/2 formalism and Floquet theorem, the spin dynamics of a spin-3/2 under rf irradiation and magic-angle...

2013
Hiroyuki Ishida

The reorientation of the tetrahedral complex anion ZnCl 4 2 and the self-diffusion of the cation in (CH3NH3)2ZnCl4 were studied by 'H NMR spin-lattice relaxation time ( 'H TX) experiments. In the second highest-temperature phase, the temperature dependence of *H TX observed at 8.5 MHz could be explained by a magnetic dipolar-electric quadrupolar cross relaxation between 'H and chlorine nuclei, ...

Journal: :Journal of magnetic resonance 1999
R Kemp-Harper B Wickstead S Wimperis

Experimentsthat selectively excite I = 32 nuclei exhibiting residual quadrupolar splittings are used to acquire 23Na NMR spectra from a range of biologically relevant samples containing sodium in ordered environments. Three complementary approaches to the analysis of such spectra are described: (i) measurement of relaxation rates, (ii) extraction of homogeneous linewidths from two-dimensional J...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2008
James G Kempf Michael A Miller Daniel P Weitekamp

The nanoscale distributions of electron density and electric fields in GaAs semiconductor devices are displayed with NMR experiments. The spectra are sensitive to the changes to the nuclear-spin Hamiltonian that are induced by perturbations delivered in synchrony with a line-narrowing pulse sequence. This POWER (perturbations observed with enhanced resolution) method enhanced resolution up to 1...

Journal: :Journal of magnetic resonance 2006
Zhehong Gan

A rotary resonance echo double resonance (R-REDOR) experiment is described for measuring heteronuclear dipolar coupling under magic-angle spinning. Rotary resonance reintroduces both dipolar coupling and chemical shift anisotropy with an rf field matching the spinning frequency. The resonance effect from chemical shift anisotropy can be refocused with a rotary resonance echo. The R-REDOR experi...

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