1. The problem statement, all variables and given/known data In an NMR spectrum a CH2 group has a peak centred at 9.81 ppm. What is the shift in Larmor frequency of the protons from that of an unshielded proton if the spectrometer magnetic field is 9.4 T? The magnetogyric ratio of an unshielded proton is γH = 26.75 × 107 rad s-1T-1 2. The attempt at a solution So 26.75 × 107 rad s-1T-1 x 9.4 T = 2.51 x 109 rad s-1 x 0.159155 = 4.00 x 109 Hz /106 = 400 MHz Then I don't really know what to do Chemical shift = v(sample)-v(reference)/v(reference) 9.81ppm = 106 x (v(sample)- 4 x 10-9/4 x 10-9) 3924 = 106 x (v(sample) x 10-6 - 400) 4324 MHz for the sample frequency which I'm sure is wrong.