Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1236976 | Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy | 2005 | 8 Pages |
Abstract
Raman spectra of propylamine (C3H7NH2) and its binary mixtures, C3H7NH2 + CH3OH with varying mole fractions of the reference system, C3H7NH2, C were recorded in two widely apart wavenumber regions, 3100-3600 cmâ1 and 1225-1325 cmâ1. In the former region, the two Raman bands at â¼3305 and â¼3326 cmâ1, obtained after the line shape analysis, which were assigned to symmetric ν(NH) and anti-symmetric ν(NH) stretching modes, respectively, show a downshift upon dilution. However, whereas the ν(NH) anti-symmetric mode shows a shift of 18.6 cmâ1, the ν(NH) symmetric mode shows a much smaller shift (5.7 cmâ1) between neat liquid and high dilution, C = 0.1. This aspect has been explained using the optimized geometries calculated employing ab initio theory (MP2 level) for the neat C3H7NH2 and its different hydrogen-bonded complexes. The linewidth versus concentration plot for the ν(NH) anti-symmetric stretching mode, however exhibits a distinct maxima at C = 0.4, which has been explained as a slight departure from the concentration fluctuation model. In the latter region, a symmetric peak is observed, which corresponds to ν(CN) stretching mode, which shows an upshift upon dilution and an almost linear concentration dependence. This has also been explained in terms of the parameters obtained from the optimized geometries of the different hydrogen-bonded complexes.
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Sunil K. Srivastava, Animesh K. Ojha, W. Kiefer, B.P. Asthana,