Q8(b)(i). Microwave activity; rotational constants of CO
(A) H₂, HCl, BrF, CH₄ and H₂O: which of these molecule(s) will show a microwave rotational spectrum? Justify your answer. (B) The first rotational absorption of ¹²C¹⁶O was observed at 3.84235 cm⁻¹ while that of ¹³C¹⁶O was observed at 3.67337 cm⁻¹. Find their rotational constants.
Answer in brief
(A) HCl, BrF and H₂O are microwave active; H₂ and CH₄ are inactive. (B) B(¹²C¹⁶O) = 1.92118 cm⁻¹; B(¹³C¹⁶O) = 1.83669 cm⁻¹.
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Coversmicrowave spectroscopyrotational constantpermanent dipole momentrigid rotorisotope effect
All parts of Question 8
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- 8(c)(iii) Fundamental vibrations of CO₂ and their IR activity5 marks