Magnetic spin and orbital moments of size-selected free iron cluster ions Fe{n}{+} (n=3-20) have been determined via x-ray magnetic circular dichroism spectroscopy. Iron atoms within the clusters exhibit ferromagnetic coupling except for Fe{13}{+}, where the central atom is coupled antiferromagnetically to the atoms in the surrounding shell. Even in very small clusters, the orbital magnetic moment is strongly quenched and reduced to 5%-25% of its atomic value while the spin magnetic moment remains at 60%-90%. This demonstrates that the formation of bonds quenches orbital angular momenta in homonuclear iron clusters already for coordination numbers much smaller than those of the bulk.
Low-frequency Raman spectra of ethanol−water binary solutions
with varying mixing ratios are measured
and presented in the form of the intrinsic Raman scattering activity,
the R(ν̄) spectra. They exhibit an
isosbestic
point at 135 cm-1 between the pure water
O−O stretching peak at 185 cm-1 and that of
pure ethanol at 110
cm-1. The R(ν̄)
spectra of the binary solutions are found to be decomposed into linear
combinations of the
R(ν̄) spectra of pure water and pure ethanol.
The plot of the coefficients of linear combinations as a
function
of ethanol mole fraction x
E has an inflection
point at x
E = 0.2, and the increasing fraction
of the ethanol
component is compensated with the decreasing fraction of the water
component. This can be explained
when ethanol−water binary solution does not get ideally mixed on the
molecular level and the hydrogen
bonds between water associates and ethanol associates become weak owing
to the collective molecular motion
or the sliding motion of the two units.
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