Investigation of Spin Tunneling in Carbon Monoxide Recombination withβHemoglobin

Abstract
A magnetic-field-induced optical linear dichroism has been observed in photolyzed β-hemoglobin at temperatures below 20 K. Nonadiabatic reaction rate theory for spinforbidden processes predicts a magnetic modulation of the tunneling rate which may account for the signal observed. The effect observed should be sensitive to crystal-field energy-level splittings for the iron atom in the heme group.