Abstracts 1999

Abstract of Publication No. 323

D. Hernandez, F. Rodriguez, M. Moreno and H. U. Güdel
Pressure dependence of the crystal field spectrum of the NH4MnCl3 perovskite: Correlation between 10Dq, Ne and Nt, and the Mn-Cl distance in MnCl64- complexes
Physica B 265, 186-190 (1999)      Full Text (PDF)      DOI-Link     

Abstract: This work investigates the pressure-dependence of the crystal field (CF) spectrum of MnCl64- complexes in NH4MnCl3. The aim is to determine the variation of 10Dq as well as the bonding parameters Ne and Nt deduced from the absorption spectra, with the Mn¯Cl distance. The selected crystal provides a perfect Oh symmetry for Mn2+ allowing a direct correlation between the pressure and the Mn¯Cl distance through the bulk modulus. Precise values of the variations of the spectroscopic parameters with P were obtained from the linear behaviour exhibited by the six single CF excitations in the 0¯60 kbar range. It is worth pointing out that an R-dependence of 10Dq on the basis of a KRn variation with n close to 7 was attained from the pressure-induced shifts. A remarkable feature is the reduction of Ne and Nt upon pressure. Although Ne < Nt due to the greater bonding character of the eg-orbitals, its variation with pressure however is smaller than that of the p-bonding t2g-related Nt parameter.

Last modified: 13.12.11 by Gabriela Frei