1304.7692 (G. P. De Sousa et al.)

Low-temperature Raman spectra of L-histidine crystal    [PDF]

G. P. De Sousa, P. T. C. Freire, J. Mendes Filho, F. E. A. Melo, C. L. Lima

We present a Raman spectroscopy investigation of the vibrational properties of L-histidine crystals at low temperatures. The temperature dependence of the spectra show discontinuities at 165 K, which we identify with modifications in the bonds associated to both the NH3+ and CO2- motifs indicative of a conformational phase transition that changes the intermolecular bonds. Additional evidence of such a phase transition was provided by differential scanning calorimetry measurements, which identified an enthalpic anomaly at ~165 K.

View original: http://arxiv.org/abs/1304.7692