High resolution nuclear magnetic resonance spectroscopy in liquids and gases at pressures up to 2500 bar

This article is the first in a series of four papers, which deal with the effect of hydrostatic pressure on the high resolution proton magnetic resonance spectra of methane, ethylene, methanol and ethanol. The present paper describes the spectrometer in which high resolution spectra can be recorded at pressures up to 2500 bar. The most essential part of the spectrometer is a beryllium copper high pressure vessel in which the sample can be rotated under pressure. The positions of the spectral lines are referred to an external reference of benzene, contained in a sealed glass capillary. Frequency modulation of the transmitter is used in the measurement of the line positions. The paper describes how the apparatus can also be used for the measurement of the density dependence of the diamagnetic volume susceptibility.