In a 400 MHz ¹H NMR spectrometer, a proton resonates 1560 Hz above tetramethylsilane, whose shift is zero. Find its chemical shift in ppm (one decimal place).
Chemical shift is the frequency separation divided by the operating frequency, times 10⁶. Thus $\delta=1560/(400\times10^6)\times10^6=1560/400=3.9$ ppm. Using MHz in the denominator directly gives Hz/MHz numerically in ppm.
More Spectroscopy: Atomic spectroscopy; Russell-Saunders coupling; Term symbols and spectral details; origin of selection rules. Rotational, Vibrational, Electronic and Raman spectroscopy of diatomic and simple polyatomic molecules. Line broadening and line widths; simple properties of Gaussian and Lorentzian line shapes. Molecular spectroscopy: Absorbance, Beer- Lambert’s law, Einstein’s coefficient, Jablonski diagram. Relationship of transition moment integral with molar extinction coefficient and oscillator strength. Basic principles of Nuclear Magnetic Resonance: Gyromagnetic ratio; Chemical shift, nuclear coupling. questions
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