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Unusually narrow spectral features are seen in fluorescence peaks from 85 Rb atoms under the action of two driving laser fields that are in a three-dimensional molasses configuration. One of the lasers, L1, is held at a fixed detuning from the "cooling" transition, while the other, L2, is scanned across the "repumping" transitions. The fluorescence peaks are split into symmetric pairs, with the separation within a pair increasing with the detuning of the L1 laser. For large detunings, additional small peaks are seen. A simple model is proposed to explain these experimental observations.

ac susceptibility and electrical resistivity studies on polycrystalline Feso "Ni"Cr2O (21» x~30) alloys, with x = 21, 23, 26, and 30, between 4.2 and 80 K, are reported. A previous dc magnetization study indicated the presence of ferro-spin-glass mixed-phase behavior in x =23 and 26 alloys while the alloys with x=21 and 30 were found to be spin-glass and ferromagnetic, respectively. The present ac susceptibility results support the above picture. In the electrical resistivity study, a low-temperature minimum in the resistivity-temperature curve is observed in all the alloys except the ferromagnetic one.