Pseudospin Dynamics of the One-DimensionalS=12XY System PrCl3Studied by Electronic Raman Scattering

Direct confirmation of the one-dimensional $S=\frac{1}{2}$ $\mathrm{XY}$ character of the interactions between the pseudospins of the ${\mathrm{Pr}}^{3+}$ ions in Pr${\mathrm{Cl}}_3$ is obtained through a study of the pseudospin dynamics by means of electronic Raman scattering, with and without a magnetic field. This is concluded from an analytic calculation of the spectral moments and from a numerical finite-chain calculation of the line shapes, both of which are in excellent agreement with the experimental data.