[填空题]
(a) Calculate the charactery71vuk:w+f9ltftqj /zc qq 9lgp6 7s1isticuplunn6mzqr9-8-h + r rotational energy, $ \frac{\hbar^2}{2I} $ for the $ \text{O}_2 $ molecule whose bond length is 0.121 nm. $\frac{\hbar^2}{2I} =$ $ \times 10^{-4}\ \text{eV}$
(b) What are the energy and wavelength of photons emitted in a $ L=2 $ to $ L=1 $ transition? $\lambda $ = mm
