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Updated: May 6, 2026

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy
Published on: June 28, 2016
Experimental boundaries of the quantum rotor induced polarization (QRIP) in liquid state NMR
Maik Icker1, Pascal Fricke, Toni Grell
1Institute of Analytical Chemistry, University of Leipzig, Johannisallee 29, 04103, Leipzig, Germany.
Abstract:
The Haupt-effect is a rather seldom used hyperpolarization method. It is based on the interdependence between nuclear spin states and rotational states of nearly free rotating methyl groups having C3 symmetry. A sudden change in temperature from 4.2 K to room temperature by fast dissolution yields considerably enhanced (13)C and (1)H resonance signals. This phenomenon is now termed quantum rotor induced polarization. More than 40 substances have been studied by this approach in order to identify them as polarizable by the 'Haupt-effect in the liquid state'. Influencing factors have been analyzed systematically. It could be concluded that substances having a high tunneling frequency, which is due to a small and narrow potential barrier, are most likely to feature quantum rotor induced polarization-enhanced signals.
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