Carlos Quintanar

Electron paramagnetic resonance studies of Eu2+ in Cs2NaLaCl6 crystals

Abstract Electron paramagnetic resonance studies performed at room temperature in Eu2+ doped Cs2NaLaCl6 single crystals (elpasolite type) showed that the paramagnetic ion occupies a trigonal symmetry site of the crystalline cubic field of the host. Room temperature spin-Hamiltonian parameters are obtained from an accurate angular variation in the (110) crystallographic plane. A possible outline for the configuration of the paramagnetic site is discussed.

EPR measurements of the spin-hamiltonian zero-field splitting parameters as a function of temperature in MN2+-doped Cs2NaLaCl6

Abstract The spin-Hamiltonian zero-field splitting parameter b 2 0 is measured as a function of temperature in Mn 2+ doped Cs 2 NaLaCl 6 single crystals (elpasolite type). The experiments showed that the Mn 2+ ion occupies two different tetragonal symmetry sites in the cubic crystalline lattice of Cs 2 NaLaCl 6 . Both sites possess principal Z-axes along 〈100〉 crystallographic directions. Electron spin resonance measurements were made at X-band frequencies (9.2 GHz) in the temperature range from 12.8 to 300 K. The present results are taken into account in order to establish a possible relation between the spin-Hamiltonian parameter b 2 0 and the temperature. A tentative determination of the Debye temperature is derived from the experimental data.

Divalent manganese in two different tetragonal sites of Cs2NaLaCl6

Electron paramagnetic resonance studies performed at room temperature in Mn2+ doped Cs2NaLaCl6 single crystals (elpasolite type) showed that the Mn2+ ion occupies two different tetragonal symmetry sites in a cubic crystalline lattice. Both sites possess principal Z‐axes along 〈100〉 crystallographic directions with large splittings (≊1.0 cm−1 and ≊0.8 cm−1) of the spectra. Several facts are taken into account in order to establish tentative models for the structural configuration of the two sites.

Facultad de Ciencias-UNAM

RESUMEN: La nanociencia en la Facultad de Ciencias de la Universidad Nacional Autonoma de Mexico es un tema de investigacion compartido tanto por grupos de investigacion formados por fisicos como por biologos. Los fisicos aplicando metodos de primeros principios de la fisicoquimica computacional estudian fragmentos especificos del genoma del ser humano donde los virus han dejado su huella. Por otra parte, los biologos aplican metodos de la nanociencia para entender mejor los nanosistemas biologicos que estan investigando. Esta situacion no debiera sorprender a nadie, si se tiene en cuenta que biologos, matematicos y fisicos comparten en la Facultad de Ciencias una larga historia. En este trabajo tambien se describe a grandes rasgos esa larga historia.