MCQ Question:
Vibrational frequency (f) of a diatomic molecule is given by
where 𝑘 is the force constant and 𝜇 is the reduced mass. For a diatomic molecule (AX), the reduce mass is given by
where 𝑚𝐴 and 𝑚𝑥 are mass of atom A and atom B respectively.
If vibrational frequencies (in wavenumber terms) of Cl2 and F2 in are 915 cm^-1 and 525 cm^-1 respectively, what is the ratio between the corresponding force constants of Cl2 and F2 (Cl2 : F2)?
(a) 5.7
(b) 6.0
(c) 6.3
(d) 6.7
(e) 7.1
The answer from MCQ is A) 5.7. I tried writing two equations for Cl2 and F2 and then dividing them but I got an answer of 1.74. How can I get 5.7?