We have investigated the optical absoration spectra corresponding to the
4A
2g→
2E
g transition of Cr
3+ in various rare earth orthochromites RCrO
3. In the case that the R
3+ ion is magnetic, an electric dipole band (R' band) was observed in the neighborhood of the Cr
3+ exciton lines. The R' bands were classified into three groups on the basis of their behaviors as follows: (1) The R' band in RCrO
3 (R=Yb and Tm) are the combined excitation of a Cr
3+ exciton and a R
3+ spin flip which is induced by the anisotropic parts of the Cr
3+-R
3+ exchange interaction. (2) The R' band in GdCrO
3 is the combined excitation of a Cr
3+ exciton and a R
3+ spin flip which is induced by the isotropic part of the Cr
3+-R
3+ exchange interaction. (3) The R' band in RCrO
3(R=Er, Ho, Dy and Tb) is the localized Cr
3+ exciton which is caused by the R
3+ spin fluctuation or by the static disorder of the R
3+ spin configuration. From the analysis of the R' band, it was elucidated that the Cr
3+-R
3+ magnetic interaction plays an important role in the Cr
3+ exciton motion in RCrO
3.
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