Rotational-quantum-number dependence of hyperfine transition intensity near the B(v′ = 14)−(v″ = 1) bandhead of ^127I_2

Abstract
Hyperfine transitions in the 14–1 band belonging to the BX system of 127I2 were studied with a cw ring dye laser and a supersonic molecular-beam technique. Hyperfine splittings of 55 rovibronic transitions were measured for P and R branches with rotational quantum numbers J = 0−30. From the measurements, J dependences of relative line strengths of the forbidden transitions (ΔF = 0 and ΔF = −ΔJ) were investigated and compared with theoretical calculations. For J ≲ 5 the relative line strengths of the forbidden transitions were found to be of the same order as those of the allowed transitions (ΔF = ΔJ). For J ≳ 5 they rapidly decreased as J increased and almost disappeared above 25. The tendency of the decrease agreed with the theoretical prediction.