Selection Rule Of Rigid Diatomic Molecule
∆J = ±1
This rule says that when schrodinger wave equation show that for this molecule we consider transitions in which J change by one unit all the other transition being spectroscopically forbidden.
For Heteronuclear diatomic molecule are microwave active molecule i.e HCl, HBr, CO, NO etc
For Homonuclear diatomic molecule are microwave inactive molecule i.e H2, Cl2, N2, O2 etc
