Question

b)What is the essential condition for a molecule to be microwave active? (5) Classify the following molecules as microwave active or microwave inactive and state the reason in each case. NO, Br2, N2O, XeF2 [Hint: N2O is a linear molecule and one of the nitrogen atoms is at the centre.]

Answer 1

NO is active

The molecule must possess a permanent dipole moment for a rotational transition in the microwave spectroscopy.

Answer 2

Answer:

• A persistent dipole moment is a need for a molecule to be microwave active. Examples of such molecules are HCl, CO, etc.
• The revolving dipole then produces an electric field that might interact with the microwave radiation's electrical component.

Second Part:

• No, and $XeF_{2}$ are active
• According to the gross selection rule, a rotational transition in microwave spectroscopy requires a molecule to have a permanent dipole moment.
• $Br_{2}$ and $N_{2} O$ are inactive

Molecule to be microwave active:

• Microwaves have no effect on molecules. Diatomic heteronuclear compounds (such CO, HF, and HCl) have. constant dipole moment (polar compound)
• Heteronuclear diatomic molecules are microwave active because rotation causes a change in the dipole, which causes contact with radiation.

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