ANISTROPY OF G-VALUES IN LOW-SPIN FERRIHAEMOGLOBIN AZIDE

Possible mechanisms which cause the large anisotropy of the low-spin ferrihaemoglobin compounds are investigated. First of all, it is shown that the anisotropy is not explained quantitively by the static Jahn-Teller effect in this biological system. Then it is shown that in the quantal region of the Jahn-Teller interaction (dynamical Jahn-Teller effect) the anisotropy in the haem plane does not appear in contrast to the results in the static case. The asymmetrical location of the azide ion is investigated as another mechanism of the anisotropy. It is shown that the two models concerning the bonding between azide and iron ion produce at most half the right magnitude of anisotropy. It is concluded that the large anisotropy in the low-spin ferrihaemoglobin azide is due to the combined action of the dynamical Jahn-Teller interaction and the rhombic crystal field of azide and imidazole. © 1969, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.