Infrared-induced processes in a disordered crystal of a tutton salt

Hole burning of the four N-D stretching bands of NH3D+ in a mixed Tutton salt [(NH4)(2)Co0.25Ni0.75(H2O)(6)(SO4)(2)], dilute in NH3D+ and HDO, has been investigated. The burning changes the orientational distribution of the NH3D+ ions. Relaxation in the dark of the altered distribution is accompanied by slower changes of the HDO molecules. The motion of the HDO molecules demonstrates long-range coupling among the orientational coordinates of the molecules in the crystal and the propagation of strain through the crystal.