The lowest quartet state of copper porphin: Zeeman experiments at 4.2 K

Zeeman experiments in a magnetic field of 75 kG on copper porphin in a single crystal of n-octane prove the lowest metastable state to be a quartet as predicted by Gouterman and colleagues. In zero magnetic field this quartet is split into two degenerate pairs, the ±$\text{1}\text{2}$ components lying at about 0.7 cm^?1 higher energy than the ±$\text{3}\text{2}$ components.