In the pure rotational microwave spectrum of a XY molecule, the adjacent lines are separated by $4 \mathrm{cm}^{-1}$. If the molecule is irradiated by a radiation of 30,000 cm-1 , the first Stokes line(in cm-1) appears at
(a)29988
(b)30012
(c)30004
(d)29996
Answer
Answer: A ✓ checked by 4AB · confidence high
Explanation
2B = 4 cm⁻¹, B = 2; the first rotational Stokes Raman line is shifted by 6B = 12 cm⁻¹: 29988 cm⁻¹ (a).