Interpretation of the Raman spectra of aqueous acid solutions in terms of the polarizability of hydrogen bonds. Part 1.—Aqueous HCl solutions

Abstract

In the Raman spectra of pure water and aqueous HCI solutions a continuous scattering is found, similar to the continuous absorption observed with the i.r. spectra of acid solutions. The continuum of energy level differences probably arises from the extremely large proton polarisability of the hydrogen bond in the HsOi grouping, since the large polarisability causes interaction effects of these hydrogen bonds with their environment, so shifting the energy levels. Below 300 cm-l an extremely strong intensity increase for the acid solution is caused by the 0 ---0 stretching vibration. One reason for this Raman intensity may be the large change of the hydrogen bond polarisability caused by the proton as a function of the 0 Q distance in the hydrogen bond (OH 0)'-. The intensity of the H2Q torsional vibrations at 780 and 450 cm-' rises, too, with increasing acid concentration, but not as strongly. This, also, may be explained by the large proton polarisability of the H-bond.

Electro-activation of potassium acetate, potassium citrate and calcium lactate: impact on solution acidity, Redox potential, vibrational properties of Raman spectra and antibacterial activity on E. coli O157:H7 at ambient temperature

“…This region generally corresponds to stretching vibrations of the hydrogen-bonded OH, so called Fermi resonance (Busing and Hornig 1961; Murphy and Bernstein 1972). The changes in the intensity in this region has also been observed in other works suggesting that this is also may due to the changes in electrolyte concentration or different enthalpies of the solutions caused by temperature (Pernoll et al 1975; Maréchal 2011). The Raman spectra intensity of the electro-activated solutions were significantly different from those of the commercial solutions of organic acids and the non-treated solutions of the salts of the used organic acids (Fig.…”

Nature and Estimation of Functional Groups on Solid Surfaces

“…This enhancement was attributed to the formation of extremely polarizable hydrogen bonds, which are also responsible for the continuous absorption in the infrared spectra of the Si0 2 /NH 3 system (see section II.A.l.a.ii). Analogous enhancements have been observed in the very low frequency Raman spectra of aqueous acid and salt solutions [306].…”

Detection of the electronic structure of iron-(iii)-oxo oligomers forming in aqueous solutions

“…66 The broad band at 1650 cm À1 corresponds to the water n 2 bending vibration. 67,70 In contrast, Raman spectra measured at the large ratio h = 2.5 exhibit additional bands characteristic for akaganeite, at 395 (Fe-OH), 550 and 720 cm À1 (FeOOH). 69 Furthermore, the occurrence of a band at 866 cm À1 with maximum intensity near h = 0.25 can be probably assigned to Fe-O-Fe motifs in dinuclear complexes.…”

“…66 Bands below 200 cm À1 are the translational vibrations of hydrogen bonded H 2 O-H 2 O or Cl-H 2 O motifs. 66,67 The 320 cm À1 band is generally assigned to Fe-Cl stretching vibrations, 66,68,69 and the shoulder at 440-480 cm À1 is due to the Fe-OH 2 stretch. 66 The broad band at 1650 cm À1 corresponds to the water n 2 bending vibration.…”