Abstract
A magnetic circular dichroism (m.c.d.) study of the interaction of molecular iodine with a variety of organic solvents has been made. The visible iodine absorption band is composed of three distinct transitions, each of which is separately identifiable in the m.c.d. spectrum, and this has made it possible to measure the blue shift of the individual bands. The linear relationship between the enthalpy of formation of the complex, -Δ
H
°
, and the blue shift, Δ
W
, is found to hold for each transition. The different slopes of the graphs of -Δ
H
°
against Δ
W
are compatible with Mulliken's interpretation of the blue shift.
From a study of the m.c.d. of the benzene-iodine charge-transfer band it is concluded that the axial configuration of the complex plays little or no role in its time-averaged geometry.