In the pure Raman rotational spectrum of ${ }^{16} \mathrm{O}_{2}$, whose electronic ground state is ${ }^{3}\Sigma_{\mathrm{g}}$, transitions between to/from
(a)Even J levels are missing
(b)Odd J levels are missing
(c)All J levels appear
(d)None of the J levels appear
Answer
Answer: A ✓ checked by 4AB · confidence high
Explanation
¹⁶O has I = 0, and for the ³Σg⁻ ground state of O₂ nuclear-spin statistics allow only odd J levels; the even J levels are missing.