Frequency domain magnetic resonance

Table 1 Zero-field splittings of molecular nanomagnets determined by frequency domain magnetic resonance spectroscopy...

Fig. 4 Comparison of Zero-Field techniques to determine the Zero-Field Splitting in Mni2Ac. (a) Frequency Domain Magnetic Resonance Spectroscopy [105]. (b) Frequency Domain Fourier-Transform Terahertz Spectroscopy [88] (Schnegg, Personal communication), (c) Terahertz Time-Domain Spectroscopy, adapted from [102]. Used with permission. 2001 American Physical Society, (d) Inelastic Neutron Scattering, adapted from [106]. Used with permission. 1999 American Physical Society. Readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. Except as provided by law, this material may not be further reproduced, distributed, transmitted, modified, adapted, performed, displayed, published, or sold in whole or part, without prior written permission from the American Physical Society...

Vongtragool S (2004) Frequency-domain magnetic resonance spectroscopy on the mnl2-acetate single-molecule magnet. PhD Thesis, Universitat Stuttgart... 

Nuclear magnetic resonance spectroscopy Interaction magnetic fields - nuclei Resonance of radiation quanta, h v Radiofrequency pulses Spectrum in time or frequency (FT) domain ... 

V. Toronov, A. Webb, J. H. Choi, M. Wolf, L. Safonova, U. Wolf, and E. Grat-ton. Study of local cerebral hemodynamics by frequency-domain near-infrared spectroscopy and correlation with simultaneously acquired functional magnetic resonance imaging. Optics Express, 9 417-427, 2001. 

The newer instruments (Figure 2.4c) utilize a radiofrequency pulse in place of the scan. The pulse brings all of the cycloidal frequencies into resonance simultaneously to yield a signal as an interferogram (a time-domain spectrum). This is converted by Fourier Transform to a frequency-domain spectrum, which then yields the conventional m/z spectrum. Pulsed Fourier transform spectrometry applied to nuclear magnetic resonance spectrometry is explained in Chapters 4 and 5. 

In most modern spectrometers resonance is observed as a function of RF energy at a constant magnetic field. A short pulse of RF radiation is applied to the sample and excites simultaneously all of the nuclei of a particular type, for example, 1H. The emitted signal is measured as the thermal population of the spin states is re-established this is known as the free induction decay (FID). An FT of the FID produces a frequency domain spectrum. 

The original linear prediction and state-space methods are known in the nuclear magnetic resonance literature as LPSVD and Hankel singular value decomposition (HSVD), respectively, and many variants of them exist. Not only do these methods model the data, but also the fitted model parameters relate directly to actual physical parameters, thus making modelling and quantification a one-step process. The analysis is carried out in the time domain, although it is usually more convenient to display the results in the frequency domain by Fourier transformation of the fitted function. 

TIME and FREQUENCY DOMAIN DATA in MAGNETIC RESONANCE SPECTROSCOPY... 

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