Assessing the Molecular Specificity and Orientation Sensitivity of Infrared, Raman, and Vibrational Sum-Frequency Spectra

Symmetry

Lea Gozdzialski¹  Ulrike Stege¹  Kuo-Kai Hung¹  Fei Chen²  DennisK. Hore² 

[1] Department of Chemistry, University of Victoria, Victoria, BC V8W 3V6, Canada;Department of Computer Science, University of Victoria, Victoria, BC V8P 5C2, Canada;

关键词: molecular orientation;    spectral unmixing;    infrared absorption;    visible-infrared sum-frequency generation;    Raman scattering;    linear programming;   

DOI  :  10.3390/sym13010042

来源: DOAJ

【 摘 要 】

Linear programming was used to assess the ability of polarized infrared absorption, Raman scattering, and visible–infrared sum-frequency generation to correctly identify the composition of a mixture of molecules adsorbed onto a surface in four scenarios. The first two scenarios consisted of a distribution of species where the polarity of the orientation distribution is known, both with and without consideration of an arbitrary scaling factor between candidate spectra and the observed spectra of the mixture. The final two scenarios have repeated the tests, but assuming that the polarity of the orientation is unknown, so the symmetry-breaking attributes of the second-order nonlinear technique are required. The results indicate that polarized Raman spectra are more sensitive to orientation and molecular identity than the other techniques. However, further analysis reveals that this sensitivity is not due to the high-order angle dependence of Raman, but is instead attributed to the number of unique projections that can be measured in a polarized Raman experiment.

【 授权许可】

Unknown