%0 Journal Article %J Review of Scientific Instruments %D 2017 %T Invited Review Article: Instrumentation for nuclear magnetic resonance in zero and ultralow magnetic field %A Tayler, MCD %A Theis, Thomas %A Tobias F. Sjolander %A John W. Blanchard %A Kentner, A %A Pustelny, S %A Pines, Alexander %A Budker, Dmitry %X

We review experimental techniques in our laboratory for nuclear magnetic resonance (NMR) in zero and ultralow magnetic field (below 0.1 μT) where detection is based on a low-cost, non-cryogenic, spin-exchange relaxation free 87Rb atomic magnetometer. The typical sensitivity is 20-30 fT/Hz1/2 for signal frequencies below 1 kHz and NMR linewidths range from Hz all the way down to tens of mHz. These features enable precision measurements of chemically informative nuclear spin-spin couplings as well as nuclear spin precession in ultralow magnetic fields.

%B Review of Scientific Instruments %V 88 %8 09/2017 %G eng %U http://aip.scitation.org/doi/abs/10.1063/1.5003347 %R https://doi.org/10.1063/1.5003347 %0 Journal Article %J Chemical Physics Letters %D 2013 %T Chemical analysis using J-coupling multiplets in zero-field NMR %A Theis, Thomas %A Blanchard, John W. %A Butler, Mark C. %A Ledbetter, Micah P. %A Budker, Dmitry %A Pines, Alexander %X

Zero-field nuclear magnetic resonance (NMR) spectroscopy is emerging as a new, potentially portable, and cost-effective NMR modality with the ability to provide information-rich, high-resolution spectra. We present simple rules for analysis of zero-field NMR spectra based on first-order perturbation theory and the addition of angular momenta. These rules allow for the prediction of observed spectral lines without numerical simulation. Results are presented for a few small organic molecules with characteristic spin topologies, demonstrating unambiguous assignment of peaks, highlighting the potential of zero-field NMR as a tool for chemical identification.

%B Chemical Physics Letters %V 580 %P 160-165 %8 08/2013 %@ 0009-2614 %G eng %U http://www.sciencedirect.com/science/article/pii/S0009261413008191 %! Chemical analysis using J-coupling multiplets in zero-field NMR %( vailable online 28 June 2013 %R http://dx.doi.org/10.1016/j.cplett.2013.06.042 %0 Journal Article %J The Journal of Chemical Physics %D 2013 %T Multiplets at zero magnetic field: The geometry of zero-field NMR %A Butler, Mark C. %A Ledbetter, Micah P. %A Theis, Thomas %A Blanchard, John W. %A Budker, Dmitry %A Pines, Alexander %K Zeeman effect %B The Journal of Chemical Physics %V 138 %P 184202-15 %8 05/14/ %G eng %U http://dx.doi.org/10.1063/1.4803144 %N 18 %! Multiplets at zero magnetic field: The geometry of zero-field NMR %0 Journal Article %J The Journal of Chemical Physics %D 2013 %T Parahydrogen-induced polarization at zero magnetic field %A Butler, Mark C. %A Kervern, Gwendal %A Theis, Thomas %A Ledbetter, Micah P. %A Ganssle, Paul J. %A Blanchard, John W. %A Budker, Dmitry %A Pines, Alexander %X

We use symmetry arguments and simple model systems to describe the conversion of the singlet state of parahydrogen into an oscillating sample magnetization at zero magnetic field. During an initial period of free evolution governed by the scalar-coupling Hamiltonian HJ, the singlet state is converted into scalar spin order involving spins throughout the molecule. A short dc pulse along the z axis rotates the transverse spin components of nuclear species I and S through different angles, converting a portion of the scalar order into vector order. The development of vector order can be described analytically by means of single-transition operators, and it is found to be maximal when the transverse components of I are rotated by an angle of ±π/2 relative to those of S. A period of free evolution follows the pulse, during which the vector order evolves as a set of oscillating coherences. The imaginary parts of the coherences represent spin order that is not directly detectable, while the real parts can be identified with oscillations in the z component of the molecular spin dipole. The dipole oscillations are due to a periodic exchange between Iz and Sz, which have different gyromagnetic ratios. The frequency components of the resulting spectrum are imaginary, since the pulse cannot directly induce magnetization in the sample; it is only during the evolution under HJ that the vector order present at the end of the pulse evolves into detectable magnetization. © 2013 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4805062]

%B The Journal of Chemical Physics %V 138 %P 234201 %8 06/2013 %G eng %U http://link.aip.org/link/?JCP/138/234201&aemail=author %N 23 %R doi: http://dx.doi.org/10.1063/1.4805062