Infrared, Polarized Raman, and SERS Spectra of Betaine Hydrogen Oxalate Monohydrate

• Published in: Journal of solid state chemistry Vol. 114; no. 1; pp. 129 - 137
• Main Authors: Philip, Daizy, Aruldhas, G.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 1995; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Infrared and raman spectra and scattering; Lattice dynamics; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Organic compounds, polymers; Phonon states and bands, normal modes, and phonon dispersion; Phonons and vibrations in crystal lattices; Physics; Solid surfaces and solid-solid interfaces; Surface structure and topography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Chemisorption; Raman spectra; Adsorption site; Colloids; Carboxylic acids; Infrared spectra; Experimental study; Surface structure; Quaternary ammonium compound; Silver; Betaine; Raman scattering; Adsorption structure; Vibrational states; Carboxylates; Organic compounds; Hydrates
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1006/jssc.1995.1019

Infrared and polarized Raman spectra of betaine hydrogen oxalate monohydrate are recorded and analyzed. The observed bands are assigned on the basis of vibrations due to oxalic acid, betaine, and water molecules. In the crystal it is found that oxalic acid molecules occupy a lower site and that betaine exists in zwitterionic form. Oxalic acid and water molecules are involved in strong hydrogen bending. Band assignments are confirmed by deuteration. Surface enhanced Raman scattering (SERS) spectra recorded in two silver colloids reveal chemisorption through different adsorption sites. The observed SERS spectra are interpreted on the basis of different adsorption sites, geometries, and adsorbate conformation/orientation. The change of the SERS spectrum with time is due to the different stabilities of the adsorbed states. The oxalic acid molecules of the compound are likely to be in a tilted orientation with respect to the silver surface.