Nuclear paramagnetism

Rollin, B V

doi:10.1088/0034-4885/12/1/302

Cited by 22 publications

(6 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The most basic CW-NMR experiment was reported in 1949 by Rollins 13 in which RF is supplied by a signal generator through a resistor to a tuned circuit resulting in a constant signal, and the magnetic field in which sample is placed is varied using sweep coils, and the amplitude of RF is monitored during the process. More energy is absorbed once the sample reaches the resonance, and hence the amplitude of the signal becomes lower until the Larmor condition is met.…”

Section: Fig 1: a Spinning Nucleus Can Be Regarded As A Magnetmentioning

confidence: 99%

Untitled

2020

IJPSR

View full text Add to dashboard Cite

Nuclear magnetic resonance spectroscopy is an absorption spectroscopic technique that helps in structural elucidation and has a wide range of applications in various fields like drug discovery and development, metabolomics, combinatorial chemistry, and food sciences. This paper gives information about nuclear magnetic resonance spectroscopy, and clear description of LC-NMR-MS, and a brief description of other hyphenations with NMR like HPLC-NMR, GC-NMR, GPC-NMR, SEC-NMR, SFC-NMR, SFE-NMR, CE-NMR, SPE-NMR, CEC-NMR, and their applications. INTRODUCTION: Nuclear Magnetic Resonance Spectroscopy: Nuclear Magnetic Resonance (NMR) spectroscopy is an absorption spectroscopic technique where the energy from an external source is absorbed and brings about resonance to an excited or higher energy state (in which nuclei in a strong constant magnetic field are perturbed by an oscillating magnetic field). The resonance occurs when the oscillation frequency matches the intrinsic frequency of the nuclei. In NMR, the energy required lies in the low energy or long-wavelength radio-frequency end of the electromagnetic spectrum. The emerging radiofrequency gets absorbed in a magnetic field consequent to the magnetic properties of nuclei arising from the axial spin.

show abstract

Section: Fig 1: a Spinning Nucleus Can Be Regarded As A Magnetmentioning

confidence: 99%

Untitled

2020

IJPSR

View full text Add to dashboard Cite

show abstract

“…Although the first successful magnetic resonance absorption experiments reported by Purcell, Torry and Pound in 1946 [3] utilized a bridge circuit, which will be discussed in the next section; the most basic CW-NMR experiment was reported in 1949 by Rollins [12] and is shown in Figure 1. A signal generator is used to supply RF to a tuned circuit through a resistor, resulting in a constant current signal, and the magnetic field in which the sample sits is varied using so-called sweep coils.…”

Section: Humble Beginningsmentioning

confidence: 99%

“…In the work of Begus and Fefer [59], attempts are made to replace as many analogue elements as possible with digital versions to improve stability and sensitivity. The system uses a similar front end to that in the original Rollin [12] paper, but with a temperature controlled DDS to supply the RF through a resistor to the tank circuit with a voltage tuned capacitor. This signal is then demodulated using the DDS as a reference before utilizing software lock-in detection on a Digital Signal Processor IC.…”

Section: Magnetometersmentioning

confidence: 99%

Advances in Electronics Prompt a Fresh Look at Continuous Wave (CW) Nuclear Magnetic Resonance (NMR)

2017

View full text Add to dashboard Cite

Continuous Wave Nuclear Magnetic Resonance (CW-NMR) was a popular method for sample interrogation at the birth of magnetic resonance but has since been overlooked by most in favor of the now more popular pulsed techniques. CW-NMR requires relatively simple electronics although, for most designs, the execution is critical to the successful implementation and sensitivity of the system. For decades there have been reports in the literature from academic groups showing the potential of magnetic resonance relaxation time measurements in industrial applications such as the production of food and drink. However, the cost, complexity and power consumption of pulsed techniques have largely consigned these to the literature. Advances in electronics and developments in permanent magnet technology now require a fresh look at CW-NMR to see if it is capable of providing cost effective industrial solutions. In this article, we review the electronics that are needed to undertake a continuous wave NMR experiment starting with early designs and journeying through the literature to understand the basic designs and limitations. We then review the more recent developments in this area and present an outlook for future work in the hope that more of the scientific community will take a fresh look at CW-NMR as a viable and powerful low-cost measurement technique.

show abstract

“…PSLs are fixed arrays of atoms, ions, or molecules with nuclear 7,9,[11][12][13][14][15][16][17][63][64][65]79,81,107 or electron 7,9,[11][12][13][14][15][16][17][63][64][65]79,[87][88][89][108][109][110] spin. Two-level PSLs ("PSLs" hereafter) result when each site is comprised of a spin-½ nucleus, paramagnetic ion, or free radical with a spin-up (magnetic moment µ parallel to external magnetic field H) ground state ↑ with energy…”

Section: A Properties Of Two-level Paramagnetic Spin Latticesmentioning

confidence: 99%

“…[1][2][3][34][35][36] The implications of the Boltzmann and Gibbs ESTs for the negative temperature debate [4][5][6]27,31 are detailed in Sec. III G. We detail the implications of the ESTs for experimental temperature measurements in PSLs 7,[13][14][15][16][17]22,54,[63][64][65][79][80][81][82][83][84][85][86][87][88][89] (Sec. III H), the potential utility of ESTs in nanothermometry 60,83,84,[90][91][92][93][94][95][96][97][98][99][100][101][102] (Sec.…”

Section: Introductionmentioning

confidence: 99%

Eigenstate-specific temperatures in two-level paramagnetic spin lattices

Masthay

Eads

Johnson

et al. 2017

The Journal of Chemical Physics

View full text Add to dashboard Cite

Increasing interest in the thermodynamics of small and/or isolated systems, in combination with recent observations of negative temperatures of atoms in ultracold optical lattices, has stimulated the need for estimating the conventional, canonical temperature T of systems in equilibrium with heat baths using eigenstate-specific temperatures (ESTs). Four distinct ESTs-continuous canonical, discrete canonical, continuous microcanonical, and discrete microcanonical-are accordingly derived for two-level paramagnetic spin lattices (PSLs) in external magnetic fields. At large N, the four ESTs are intensive, equal to T, and obey all four laws of thermodynamics. In contrast, for N < 1000, the ESTs of most PSL eigenstates are non-intensive, differ from T, and violate each of the thermodynamic laws. Hence, in spite of their similarities to T at large N, the ESTs are not true thermodynamic temperatures. Even so, each of the ESTs manifests a unique functional dependence on energy which clearly specifies the magnitude and direction of their deviation from T; the ESTs are thus good temperature estimators for small PSLs. The thermodynamic uncertainty relation is obeyed only by the ESTs of small canonical PSLs; it is violated by large canonical PSLs and by microcanonical PSLs of any size. The ESTs of population-inverted eigenstates are negative (positive) when calculated using Boltzmann (Gibbs) entropies; the thermodynamic implications of these entropically induced differences in sign are discussed in light of adiabatic invariance of the entropies. Potential applications of the four ESTs to nanothermometers and to systems with long-range interactions are discussed.

show abstract

Nuclear paramagnetism

Cited by 22 publications

References 36 publications

Untitled

Untitled

Advances in Electronics Prompt a Fresh Look at Continuous Wave (CW) Nuclear Magnetic Resonance (NMR)

Eigenstate-specific temperatures in two-level paramagnetic spin lattices

Contact Info

Product

Resources

About