抄録
Five sharp absorption lines of Mn(CH3COO)2·4H2O were found in the violet region at liquid helium temperature. The line at 24,496 cm−1 and the quartet lines between 24,695 cm−1 and 24,770 cm−1 were assigned to the transitions from the ground state 6A1 to the excited states 4A1 and 4E respectively. These transitions are caused by an electric dipole. The magnetic field dependence of relative intensities of these lines at 1.3°K was investigated, and it was concluded that the ordered state below 3.18°K is ferrimagnetic, that the preferred axis is the a axis and that the most difficult axis is the b axis. The results of susceptibility measurements and electron spin resonance were consistent with the present conclusion.
