On the Hyperfine Structure of InH and the Theory of the Hyperfine Structure of Molecules in Hund's Case (C)

Abstract

The hyperfine structure in the ³Π₁ state of InH, which deviates strongly from the magnetic hyperfine interval rule, is explained by the electric quadrupole interaction of the In nucleus. The quadrupole coupling constant for the ³Π₁ (v=0) state eQq_π is +0.1 cm⁻¹±100%. The off‐diagonal quadrupolar interaction, namely the eQ sin²θ exp (±2iφ)/r³ part, gives an F‐dependent contribution to the Λ‐type doubling of the ³Π₁ (v=0) state, eQq′ = +0.066 cm⁻¹(2000 Mc/sec)±50%. An upper limit to the quadrupole coupling constant of the X ¹Σ⁺ (v=0) state is ∼|eQqx|≳0.07 cm⁻¹±100%. The theory of hyperfine structure in Hund's Case (c) is discussed, and the matrix elements of the hyperfine interactions are evaluated for two Case (c) coupling schemes for a diatomic molecule with two nuclear spins. The matrix elements are evaluated by the generalization of Van Vleck's method of reversed angular momenta to spherical tensor form.