Self-bunching in an electron beam during passage through a resonantly absorbing medium

Abstract

A new first-order phase transition at T = 92 K has been detected in single crystals of ((CH,),N) MnCI, by means of several optical techniques. The phase transition displays a large thermal hysteresis, A T = 12 K. Coexistence of phases below 92 K is also detected. The sensitivity of the optical absorption of the crystal, as well as that of emission, excitation and lifetime of MnC$ units for detecting this phase transition is analysed in detail. The results are also compared with those corresponding to the P112,/n-P12,/cl phase transition at T = 171 K.