(a) Explain why quantisation of energy occurs. What experimental evidence is [5]there to indicate that energy is quantised?-The Boltzmann equation for the difference in population between two energylevels is:-\frac{n_{\text {uper }}}{n_{\text {lower }}}=\exp \left(\frac{-\Delta E}{k T}\right)-where h is Planck's constant, yis the gyromagnetic ratio (which equals 42.58×10Hz Tesla for 'H), and B is the applied magnetic field (in Tesla).-O Describe qualitatively the effects on the populations of the energy states of a six [4]level system, where the gap between each subsequent level is approximately2x102 J, on decreasing the temperature from 300 K to 100 K.-In NMR spectroscopy, the energy gap between the ground and excited states is given by:-\Delta E=\frac{h \gamma B}{2 \pi}-where AE is the energy gap between the states (in J), k is the Boltzmann constant,and Tis the temperature.-Calculate the population difference between the ground and excited states for 'H atB = 7 Tesla and 300 K, and hence comment on the sensitivity of NMR as a spectroscopic technique.-Calculate the wavelength of the electromagnetic radiation that would be absorbed in the transition in part (c). In what part of the electromagnetic spectrum does this radiation lie?-For electronic spectroscopy, deltaE =1.97 x 10 J. Comment on the consequences of this value for the spectroscopic technique.-• Peaks observed in electronic spectroscopy are broad (Av = 1.6 MHz), where as those observed in NMR spectroscopy are very narrow (Av= 1.6 Hz). Explain this difference, and also explain how it affects the uses of the two spectroscopic methods.

Physical Chemistry(Chemistry)

Expert answer

100% Verified

Back

+

1/3

x

Sign Up to continue

You are just one step away from getting connected
to an expert tutor ! Hurry Up !!

Post your query, Signup and get connected
to a human operator instantly.