A Note on the Stark Effect in Diatomic Molecules

Abstract
The hyperfine splitting of the energy levels of a polar diatomic molecule in a constant electric field caused by the presence of I · J interactions between each nucleus and the other charges of the molecule and a quadrupole interaction involving one of the nuclei is calculated. The calculation explains recent measurements of Trischka on molecular beams of CsF and KF. For weak fields a method is given for computing the fine structure splitting resulting from any form of interaction, provided one nucleus interacts more strongly than the other.