Vibrational spectra of α-amino acids in the zwitterionic state in aqueous solution and the solid state: DFT calculations and the influence of hydrogen bonding
Chowdhry, Babur Z., Dines, Trevor J., Jabeen, Saima and Withnall, Robert (2008) Vibrational spectra of α-amino acids in the zwitterionic state in aqueous solution and the solid state: DFT calculations and the influence of hydrogen bonding. The Journal of Physical Chemistry A, 112 (41). pp. 10333-10347. ISSN 1089-5639 (Print), 1520-5215 (Online) (doi:10.1021/jp8037945)Full text not available from this repository.
The zwitterionic forms of the two simplest alpha-amino acids, glycine and l-alanine, in aqueous solution and the solid state have been modeled by DFT calculations. Calculations of the structures in the solid state, using PW91 or PBE functionals, are in good agreement with the reported crystal structures, and the vibrational spectra computed at the optimized geometries provide a good fit to the observed IR and Raman spectra in the solid state. DFT calculations of the structures and vibrational spectra of the zwitterions in aqueous solution at the B3-LYP/cc-pVDZ level were found to require both explicit and implicit solvation models. Explicit solvation was modeled by inclusion of five hydrogen-bonded water molecules attached to each of the five possible hydrogen-bonding sites in the zwitterion and the integration equation formalism polarizable continuum model (IEF-PCM) was employed, providing a satisfactory fit to observed IR and Raman spectra. Band assignments are reported in terms of potential-energy distributions, which differ in some respects to those previously reported for glycine and l-alanine.
|Uncontrolled Keywords:||density-functional theory, generalized gradient approximation, mechanical force-field, many-body interaction, l-alanine, ab-initio, glycine/chemistry, Water/chemistry, theoretical observations, molecular-interactions, circular-dichroism|
|Subjects:||Q Science > QD Chemistry|
|School / Department / Research Groups:||School of Science|
School of Science > Department of Life & Sports Science
|Last Modified:||14 Aug 2013 15:57|
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