Raman scattering and Fourier-transform infrared (FT-IR) attenuated transmission ref
lectance (ATR) spectraof two
![](/images/gifchars/a<font color=)
lpha.gif" BORDER=0>-amino acids (
![](/images/gifchars/a<font color=)
lpha.gif" BORDER=0>-AAs), i.e., g
lycine and
leucine, were measured in H
2O and D
2O (at neutra
l pH andpD). This series of observed vibrationa
l data gave us the opportunity to ana
lyze vibrationa
l features of bothAAs in hydrated media by density functiona
l theory (DFT) ca
lcu
lations at the B3LYP/6-31++G*
leve
l.Harmonic vibrationa
l modes ca
lcu
lated after geometry optimization on the c
lusters containing each AA and12 surrounding water mo
lecu
les, which represent primary mode
ls for hydration scheme of amino acids, a
llowedus to assign the main observed peaks.