Hardware modification of a 7Â mm MAS NMR probe to a single-crystal goniometer

Tensorial terms of the Hamiltonian can be measured by solid-state single-crystal nuclear magnetic resonance (NMR) spectroscopy which requires a goniometer NMR probehead. Goniometer probes; however, are not standard parts of solid NMR spectrometers and are available only at a much higher price than magic-angle spinning (MAS) probeheads widely used in research. Due to requirements of MAS experiments, modern probeheads are designed for small ceramic rotors, which are 1-4 mm in diameter, to reach very high angular frequencies, so there are several older 7 mm MAS probeheads used rarely todays in NMR laboratories. In this paper, a simple method is presented how to rebuild step-by-step a 7 mm Bruker MAS probehead to be suitable for single-crystal spectroscopy. In the second part 31P chemical shift tensors of Na4P2O7·10H2O are determined to demonstrate the functionality of the rebuilt probehead.