Nuclear alignment

This concept has originally been named PASADENA (Parahydrogen And Synthesis Allow Dramatically Enhanced Nuclear Alignment) [6], but the spectroscopic method based on this phenomenon has subsequently also been called PHIP (Para-Hydrogen Induced Polarization) [7]. In this chapter the abbreviation PH IP will be used throughout. 

The fundamental principle governing the NMR technique centres on the induction of transitions between different nuclear Zeeman levels of a particular nucleus. To cause these transitions, a variable radiofrequency (RF), referred to as B, acts perpendicular to the applied magnetic field (B0), which is causing the nuclear alignments. When the frequency of the applied RF is identical to the precessional frequency (w0) of the nuclei being observed, a transition between nuclear spin states occurs. 

Bowers CR, Weitekamp DP. 1987. Para-hydrogen and synthesis allow dramatically enhanced nuclear alignment. J Am... 

The transformation of this molecular rotational order into nuclear spin order during the hydrogenation reaction leads to typical polarization patterns in the NMR spectra of the hydrogenation products. Depending on whether the experiment is performed inside or outside of a magnetic field (see Fig. 21.6), these types of experiments have been referred to under the acronyms PASADENA (Para-hydrogen and Synthesis Allow Dramatically Enhanced Nuclear Alignment) or... 

ALTADENA (Adiabatic Longitudinal Transport After Dissociation Engenders Nuclear Alignment), is observed. Under these conditions the spectra are much... 

ALTADENA adiabatic longitudinal transport after dissociation engenders nuclear alignment AM-1 hydrophobic nanosilica... 

PASADENA parahydrogen and synthesis allow dramatically enhanced nuclear alignment... 

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