Hyperfine Interactions in the v₃=1 Exited State of Methane

Abstract

The magnetic hyperfine interactions in the triply degenerate vibrational state of ¹²CH₄ are theoretically studied. The spin-vibration interaction is introduced as well as the spin-spin and spin-rotation interactions to obtain the explicit expressions of matrix elements of the hyperfine energy. The numerical calculations are carried out for the 6₇ F₁⁽²⁾ and A₁ sublevels in the v₃=1 exited state and a comparison is made with a recent measurement of Hall and Bordé on the F₁⁽²⁾ line.