Currently nmrglue's unit_conversion object calculates ppm values using the observational/operating frequency, spectral width, and carrier frequency. The correct method for calculating PPM values uses the frequency of a reference compound. An option to provide this value (or extract it from file dictionaries when available) and use it in PPM calculation should be added to the unit_conversion object.
Currently nmrglue's unit_conversion object calculates ppm values using the observational/operating frequency, spectral width, and carrier frequency. The correct method for calculating PPM values uses the frequency of a reference compound. An option to provide this value (or extract it from file dictionaries when available) and use it in PPM calculation should be added to the unit_conversion object.