A Method for Measurement of Spin-Spin Couplings with sub-mHz Precision Using Zero- to Ultralow-Field Nuclear Magnetic Resonance

摘要

We present a method which allows for the extraction of physical quantitiesdirectly from zero- to ultralow-field nuclear magnetic resonance (ZULF NMR)data. A numerical density matrix evolution is used to simulate ZULF NMR spectraof several molecules in order to fit experimental data. The method is utilizedto determine the indirect spin-spin couplings ($J$-couplings) in these, whichis achieved with precision of $10^{-2}$--$10^{-4}$ Hz. The simulated andmeasured spectra are compared to earlier research. Agreement and precisionimprovement for most of the $J$-coupling estimates are achieved. Theavailability of an efficient, flexible fitting method for ZULF NMR enables anew generation of precision-measurement experiments for spin-dependentinteractions and physics beyond the Standard Model.