Level-crossing spectroscopy of diatomic molecules and excited state coupling parameters; ϱ-type doubling in 2Σ states

Abstract

It is pointed out that zero-field level-crossing spectroscopy provides a method for measuring coupling in excited states which is often small compared to Doppler line widths. Such couplings as nuclear spin-electron spin and nuclear rotation-electron spin are removed by application of small magnetic fields often in a simple way. If they depend upon one parameter the Zeeman effect during decoupling is predictable. In the example of NS coupling in a 2Σ state, the splitting parameter for this “ϱ-type” doubling is of this type. Its determination is discussed.