RESUMEN
Inelastic neutron scattering spectra are reported for orthorhombic ErNiAl(4) at temperatures ranging from 2.1 to 280 K. The neutron transitions are interpreted in terms of three reliably identified excited crystal field (CF) levels and four tentative excited levels for the J = 7/2 ground term of Er(3+) at the single Er site. A shift in transition peak energy between 2.1 and 8.6 K is attributed to Zeeman splitting induced by magnetic order of the Er sub-lattice below T(N) = 5.8 K. With the aid of a suite of possible (155)Gd-Mössbauer spectroscopy derivations of the rank n = 2 CF parameters and a simple point charge model calculation of within-rank ratios for the higher rank (n = 4,6) parameters, estimates are made for all nine CF parameters required for the orthorhombic C(2v) (mm) Er-site symmetry.