The penetration of chemical reagents through human hair after bleaching has been spatially characterized using infrared microspectroscopy (IMS) with a synchrotron source. Chemical imaging of hair cross sections before and after bleaching was achieved with high contrast, using the peptide and lipid mid-infrared vibrational bands which are characteristic of hair. The ability to make images using functional groups as a contrast mechanism can be applied to studies of other chemical groups, if present, in the structure of the hair. As an example we show how the penetration of an organic active reagent in the hair structure can be quantified with a spatial resolution of few microns. These results demonstrate that synchrotron IMS is a powerful tool for characterizing chemical interactions of hair samples with specific cosmetic materials.

We employed infrared spectroscopy along with complementary lattice dynamics and spin density calculations to investigate pressure-driven local structure distortions in the copper coordination polymer Cu(pyz)F(2)(H(2)O)(2). Here, pyz is pyrazine. Our study reveals rich and fully reversible local lattice distortions that buckle the pyrazine ring, disrupt the bc-plane O-H···F hydrogen-bonding network, and reinforce magnetic property switching. The resiliency of the soft organic ring is a major factor in the stability of this material. Interestingly, the collective character of the lattice vibrations masks direct information on the Cu-N and Cu-O linkages through the series of pressure-induced Jahn-Teller axis switching transitions, although Cu-F bond softening is clearly identified above 3 GPa. These findings illustrate the importance of combined bulk and local probe techniques for microscopic structure determination in complex materials.

Far-infrared transmission through normal-state films of V3Si, Nb3Ge, and Nb has been measured between, 30 and 310 cm '. The data for V3Si followed the Drude model at low frequencies with constant scattering time and plasma frequency, but led to frequency-dependent Drude parameters above 150 -240 cm . This behavior is interpreted as arising from electron-phonon and impurity scattering effects, with the latter exhibiting a frequency dependence due to the variable electronic density of states. Nb36e also displayed high-frequency deviations from the Drude model whereas Nb did not. These characteristics are consistent with the electron-phonon behavior of each material. For V3Si, Nb3Ge, and Nb, respectively, the impurity scattering times were found to be 3.7&&10 0.7X10 '", and 1.0/10 ' sec and the bare plasma frequencies were determined as 2.9, 4.0, and 10 eV.

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