Modelling J-coupling in NMR Spectra at Low and Ultra-low Magnetic Fields

Modeling of low-field NMR spectra with indirect spin-spin interaction (J-coupling) is not included in popular NMR software. Modeling NMR spectra for cases of various magnetic fields is necessary not only for the interpretation of spectra, but also for the planning of experiments. The developed versions of the program make it possible to obtain model NMR spectra with J-coupling at any values of the magnetic field. As examples, the real proton NMR spectra of triethyl phosphate at different magnetic fields are considered in comparison with model ones. The peculiarities of NMR spectra at certain values of magnetic field are discussed.