Question

Rotational constant value in diatomic molecules depends on .....

Answer 1

Answer is - The moment of inertia of the molecule

Diatomic molecules with the general formula AB have one normal mode of vibration which involves the stretching of the A-B bond. In the gas phase the molecule can rotate about an axis.

The rotational energy is given by

Fv (J) = Bv J (J + 1) - DJ2 (J + 1)2

where J is the rotational quantum number

           D is the centrifugal distortion constant

The rotational constant depends on the moment of inertia of the molecule which varies with the vibrational quantum number.