3. *D2* Rotations about a covalent bond, such as the carbon-carbon bond in ethane, are hindered byforces between other chemical groups attached to the bonded atoms. The potential energy U due tothese forces typically looks something like this: 0 11¢ 211′ Sketch the heat capacity for this rotational degree of freedom as a function of temperature! Here are some things to keep in mind: (a) When rotational energy is much less than the barriersseparating potential energy minima (AE), the motion is oscillatory. In other words, it is like a harmonicdegree of freedom. (b) When rotational energy is much greater than AE, the motion is essentiallyunhindered. In other words, it is like a free rotation. (c) Imagine that the spacing between Vibrationalenergy levels is small compared to AE, so that the high-temperature limit of harmonic motion is reachedbefore rotations become unhindered. Label the temperature AE/kB on your plot. (4 pts)