Resonant inelastic scattering in dilute magnetic semiconductors by soft X-ray fluorescence spectroscopy

1-x Mn_xS (where 0.05<x<1) were measured as the energy of the exciting radiation was tuned across the S and Mn-L_2,3 absorption edges of these compounds. Strong resonance peaks in Mn-L emission spectra and the systematic appearance of new spectral features in S-L emission spectra were observed. Partial substitution of Zn by a magnetic Mn ion results in strong hybridization of the Mn 3d orbitals with the sp band of the host semiconductor. A detailed study of resonant inelastic scattering in the vicinity of the S and Mn-L_2,3 absorption edges of these DMS is presented. Received: 6 March 1997     

Cholesteric liquid crystal displays as optical sensors of barbiturate binding

The influence on the optical properties of cholesteric liquid crystal displays (LCDs) was examined for neutral molecule binding by mesogen/receptors in the mesomorphic phase. The motivation was to prepare neutral molecule sensors that use a colour change to signal analyte binding. A receptor that binds barbiturate analytes was modified with two or one cholesteryl groups to yield compounds 2 and 3, respectively. LCDs were prepared by incorporating one of the receptor/mesogen compounds into a cholesteric LC blend along with a potential H-bonding guest. The optical properties of the LCDs were then determined by measuring the absorbance of the displays. For various LCDs, the colour of the display depended upon several factors: the amount of guest molecule used, the number of cholesteryl side chains on the receptor and the mole concentration of receptor/mesogen in the blend. In particular, complementary host/guest binding of H-bonding analytes by the bis(cholesteryl) receptor 2 in a cholesteric LCD caused a change of up to +70 nm, which was observed by the naked eye as a blue-to-orange colour change. Control experiments confirm that the colour of an LCD is a consequence of molecular recognition in the mesomorphic phase.     

High-spin structure of yrast-band in 78Kr

Lifetime of levels up to 22⁺, have been measured in ⁷⁸Kr and an oblate shape is assigned to the ground state using the CSM and the configuration dependent shell correction calculations. Calculations further show that ⁷⁸Kr is highly γ-soft nucleus. The experimental Q _t values coupled with theoretical calculations indicate an oblate shape for ⁷⁸Kr at low spins and triaxial shape at higher spins