A New Graphical User Interface for Teaching NMR

Abstract

The classical Nuclear Magnetic Resonance (NMR) vector model is known to be very effective and useful in teaching basic NMR 1D pulse sequences such as spin echo. For more complicated spin systems, density matrix calculation is often used. This method is known to be very complicated and not easy to follow after couple steps. Students usually get lost within the calculation and loose the physical meaning of the effect of different NMR pulses and other operations (chemical shifts, scalar-couplings) on the spin-system under investigation. As a compromise, another methodology has been developed which depends on the spin angular momentum operators. This is known as product operator formalism which involves less mathematical calculations, but still requires the user to know the correct outcome of different NMR pulses, scalar couplings and chemical shifts on different spin operators. We have developed product operator graphical user interface (OP-GUI) using MATLAB software that is capable of calculating product operators of up to four-coupled ½ spin systems. The effect of NMR pulses, scalar- coupling and chemical shifts on the spin system under investigation can be easily calculated. In this paper, several examples are given as prove of concept to show the capability and flexibility of the obtained OP-GUI in dealing with spin systems. We believe the obtained calculator is an effective teaching tool for new students in NMR and will help them to better understand and interpret complicated NMR pulse sequences applied on up to four weakly coupled ½ spin systems.