The emission spectrum of the [Math] ion : fermi resonance between the 100 and 020 levels of the [Math] ground state of [Math] and [Math] ions

Several sets of [Math] bands have been identified in the [Math] band system of [Math] and [Math] ions. The relative position of the six 2Пg components of the 100 and 020 levels of the ground state has been determined and vibronic parameters, W1, W2, εω2 ν1and 2ν2 have been derived for this state.